Anti-AXL Antagonistic Antibodies

ABSTRACT

Described are antibodies that specifically bind to the Axl protein and inhibit the interaction between Axl and the Axl-ligand, Gas6. Also disclosed are methods for the production and use of the anti-Axl antibodies.

This application is a continuation of U.S. application Ser. No. 16/224,935 filed Dec. 19, 2018, which is a continuation of U.S. application Ser. No. 15/533,049 filed Jun. 5, 2017, which is a national phase entry pursuant to 35 U.S.C. § 371 of International Application No. PCT/EP2015/080654 filed Dec. 18, 2015, which claims the benefit of priority of Great Britain Application No. 1422605.4 filed Dec. 18, 2014, each of which is incorporated by reference herein in its entirety for any purpose.

INCORPORATION OF SEQUENCE LISTING

This application contains a sequence listing, submitted herewith electronically, containing the file named “P35151US02-110456500026_ST26.xml” which is 47,459 bytes in size and was created on Feb. 16, 2023, and which is herein incorporated by reference in its entirety.

The present disclosure relates to antibodies that specifically bind to the Axl protein. Also disclosed are methods for the production and use of the anti-Axl antibodies.

BACKGROUND

Axl is a member of the TAM (Tyro3-Axl-Mer) receptor tyrosine kinases (RTK) that share the vitamin K-dependent ligand Gas6 (growth arrest-specific 6). TAM family RTKs regulate a diverse range of cellular responses including cell survival, proliferation, autophagy, migration, angiogenesis, platelet aggregation, and natural killer cell differentiation. Axl is expressed in many embryonic tissues and is thought to be involved in mesenchymal and neural development, with expression in adult tissues largely restricted to smooth muscle cells (MGI Gene Expression Database; www.informatics.jax.org). Axl activation is linked to several signal transduction pathways, including Akt, MAP kinases, NF-κB, STAT, and others. Originally identified as a transforming gene from a patient with chronic myelogenous leukaemia, Axl has since been associated with various high-grade cancers and correlated with poor prognosis.

Axl receptor overexpression has been detected in a wide range of solid tumours and myeloid leukaemia (Linger et al, Adv Cancer Res. 100: 35, 2008; Linger et al, Expert Opin Ther Targets. 14:1073, 2010).

Axl expression correlates with malignant progression and is an independent predictor of poor patient overall survival in several malignancies including pancreatic (Song et al, Cancer. 117:734, 2011), prostate (Paccez et al, Oncogene. 32:698, 2013), lung (Ishikawa et al. Ann Surg Oncol. 2012; Zhang et al, Nat Genet. 44:852, 2012), breast (Gjerdrum, Proc Natl Acad Sci USA 107:1124, 2010), colon cancer (Yuen et al, PLoS One, 8:e54211, 2013) and acute myeloid leukaemia (AML) (Ben-Batalla et al, Blood 122:2443, 2013).

Axl signal transduction is activated by a protein ligand (Gas6) secreted by tumour associated macrophages (Loges et al, Blood. 115:2264, 2010) or autocrine mechanisms (Gjerdrum, Proc natl Acad Sci USA 107:1124, 2010), that drives receptor dimerization, autophosphorylation and downstream signalling, such as via PI3 kinase (PI3K)-AKT, particularly AKT and mitogen-activated protein kinase (MAPK) pathways (Korshunov, Clinical Science. 122:361, 2012). Heterodimerization with other tyrosine kinase receptors, e.g. epidermal growth factor receptor (EGFR), is also reported to occur (Linger et al, Expert Opin Ther Targets. 14:1073, 2010; Meyer et al Science Signalling 6:ra66, 2013).

Aberrant activation of Axl in tumour cells is widely associated with acquired drug resistance to targeted therapeutics in vitro and in vivo (Zhang et al. Nat Genet. 44: 852, 2012; Byers et al. Clin Cancer Res. 19: 279, 2013). Axl-targeting agents block tumour formation, metastasis and reverse drug resistance (e.g. to erlotinib) by reversing EMT/CSC characteristics in several experimental cancer models, including triple negative breast cancer, hormone resistant prostate cancer and adenocarcinoma of the lung (Holland et al Cancer Res 70:1544, 2010; Gjerdrum, Proc natl Acad Sci USA 107:1124, 2010; Zhang et al. Nat Genet. 44: 852, 2012; Paccez et al, Oncogene. 32:698, 2013).

Other applications relating to Axl and anti-Axl antibodies include EP2267454A2 [Diagnosis and prevention of cancer cell invasion measuring . . . Axl—Max Planck]; WO2009063965 [anti Axl—Chugai Pharmaceutical]; WO2011159980A1 [anti-Axl—Genentech], WO2011014457A1 [combination treatments Axl and VEGF antagonists—Genentech]; WO2012-175691A1 [Anti Axl 20G7-D9—INSERM], WO2012-175692A1 [Anti Axl 3E3E8 INSERM]; WO2009/062690A1 [anti Axl—U3 Pharma] and WO2010/130751A1 [humanised anti Axl—U3 Pharma].

In view of the role of Axl in tumourigenesis, it is desirable to identify further antibodies with advantageous properties that specifically bind Axl. The present disclosure concerns such antibodies.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1

Overlay plots of sensograms from the binding analyses showing interactions of MAbs 10C9 and 10G5 with recombinant human (rh) Axl, rhMer and rhTyro3. The curves after subtracttion of blank surface signals are shown.

FIG. 2

Biacore analyses of ligands (MAb 10C9, MAb 10G5 and rmGas6) interacting with a sensor chip CM5 coated with rhAxl, recombinant murine (rm) Axl and rhTyro3. The curves after subtraction of blank surface signals are shown.

FIG. 3

Biacore analyses of ligands (MAbs 10C9 and 10G5) interacting with a sensor chip CM5 coated with recombinant human Axl (rhAxl) and Axl antigen from cynomolgus monkey (cyno-Axl). The curves after subtraction of blank surface signals are shown.

FIG. 4

Kinetic analysis of MAbs 10C9 and 10G5 interacting with rhAxl immobilized on the surface of the Biacore sensor chip. Overlay plots of sensograms for different antibody concentrations (1.3-666.7 nM for 10C9 and 0.3-166.7 nM for 10G5) are shown. The precise kinetic analysis was performed using BIA evaluation software and curve fitting according to 1:1 Langmuir binding model. The affinity constants (kinetic and steady state) as well as the calculated half-live of antigen binding at 25° C. are shown in Table 1, below.

TABLE 1 On-rate Off-rate Half-life MAb (k_(on); M⁻¹s⁻¹) (k_(off); s⁻¹) K_(D) (M) (t_(1/2); min) 10C9 1.61 × 10⁶ 2.89 × 10⁻⁴ 1.80 × 10⁻¹⁰ 39.97 min 10G5 8.29 × 10⁵ 4.39 × 10⁻⁴ 5.30 × 10⁻¹⁰ 26.32 min

FIG. 5

Analysis of the competition between MAbs 10C9 or 10G5 (1st sample) and anti-Axl MAb MAB154 (R&D Systems), antibodies 10C9 and 10G5, rhGas6 and rmGas6 (2nd samples) using Biacore 3000. The overlay plot of sensograms using different 2nd samples is shown. Start points of injections of the 1st sample (10C9 or 10G5) and the 2nd sample are indicated with arrows.

FIG. 6

The effect of anti-Axl antibodies on the development on three-dimensional (3D) organotypic tumour masses. Highly aggressive human mammary carcinoma cells MDA-MB-231 were treated with either control IgG (shown in the middle upper panel) or anti-Axl MAbs (lower panels) while growing in the presence of extracellular matrix, thus creating 3D organotypic models. As positive control, MDA-MB-231 cells with knocked-down Axl expression are shown.

FIG. 7

Effect of anti-Axl antibodies 10C9 and 10G5 on established 3D organotypic tumour masses. The developed 9-days old stellate-shaped 3D organoid masses of human mammary carcinoma cells (MDA-MB-231) were treated with either control IgG or anti-Axl antibodies 10C9 and 10G5 for 72 hours. Images were captured using bright field; arrows indicate apoptotic, degrading stellate-shaped cells.

FIG. 8

Western blot analysis illustrating effect of treatment with either antibodies of multikinase inhibitor Foretinib on Axl receptor expression. Highly aggressive human mammary carcinoma cells MDA-MB-231 were treated with either antibodies (irrelevant IgG control and anti-Axl MAbs 10C9, 10G5 and MAb #3) or Foretinib for 24 hrs before loading on SDS-PAA gel. The levels of actin protein were used as loading controls.

FIG. 9

Western blot analysis illustrating inhibition of Gas6-mediated Axl signalling in the presence of mouse monoclonal antibodies 10C9 and 10G5. Phosphorylation of Akt on Ser⁴⁷³ was used as surrogate readout for Axl activity. M, molecular weight markers. Immunoblots of total cell lysates were probed with anti-phospho-Akt (Ser⁴⁷³), or anti-GAPDH (glyceraldehyde 3-phosphate dehydrogenase) as loading control.

FIG. 10

Amino acid sequences of the VH and VL domains derived from anti-Axl monoclonal antibodies 10C9 (SEQ ID NOs: 3 and 4, respectively) and 10G5 (SEQ ID NOs: 21 and 22, respectively). The CDR regions of the heavy and light chains are underlined. The potential Nglycosylation site in CDR-H1 of 10C9 VH domain is shown in bold.

Also included is the sequence of a 10G5 VH variant wherein the glutamine (Q) at position 1 of the VH domain is substituted with a glutamate (E); this variant is termed “10G5 [Q1E]” (SEQ ID NOs: 45 and 22).

FIG. 11

Dose-dependent binding of anti-Axl mouse antibody 10C9, its chimeric (mouse variable/human constant) counterpart (c10C9) and the chimeric variant of antibody 10G5 (c10G5) to Axl-positive cells. Different concentrations of mouse and chimeric antibodies were tested in flow cytometry for binding to triple-negative breast cancer cell line MDA-MB-231. The bound mouse and chimeric antibodies were detected with APC-conjugated donkey F(ab′)₂ fragments specific for either mouse IgG (H+L), 1:500 dilution, or human IgG (H+L), 1:300 dilution, respectively (both from Jackson ImmunoResearch). The cell staining was measured using Accuri C6 flow cytometer (BD Biosciences). MFI, geometric mean fluorescence intensity.

FIG. 12

Overlay plots of sensograms from the Biacore binding analyses showing interactions of the chimeric antibodies c10C9 and c10G5 and their murine counterparts with recombinant human (rh) Axl. The curves after subtraction of blank surface signals are shown.

FIG. 13

Kinetic analysis of chimeric antibodies c10C9 and c10G5 interacting with rhAxl immobilized on the surface of the Biacore sensor chip. Overlay plots of sensograms for different antibody concentrations (1.3-666.7 nM for c10C9 and 0.3-166.7 nM for c10G5) are shown. The precise kinetic analysis was performed using BIA evaluation software and curve fitting according to 1:1 Langmuir binding model. The affinity constants (kinetic and steady state) as well as the calculated half-live of antigen binding at 25° C. are shown in Table 2, below.

TABLE 2 On-rate Off-rate Half-life MAb (k_(on); M⁻¹s⁻¹) (k_(off); s⁻¹) K_(D) (M) (t_(1/2); min) c10C9 2.16 × 10⁶ 2.19 × 10⁻⁴ 1.02 × 10⁻¹⁰ 52.75 min c10G5 1.64 × 10⁶ 1.69 × 10⁻⁴ 1.03 × 10⁻¹⁰ 68.36 min

FIG. 14

Inhibition of A549 xenograft tumour growth by chimeric antibody 10G5. The antibody was administrated intraperitoneally at 20 mg/kg, twice a week, starting when the mean tumour size reached 100 mm³. Tumour growth curves for the groups treated with either vehicle (sterile PBS) or chimeric 10G5 are shown. Error bars represent standard error of the mean (SEM). Statistical analysis was performed using two-way ANOVA. **, P<0.01.

FIG. 15

Inhibition of Mv4-11 xenograft tumour growth by the chimeric antibody 10G5. The antibody was administrated intraperitoneally at 30 mg/kg, twice a week, starting when the mean tumour size reached 200 mm³. Tumour growth curves for the groups treated with either vehicle (sterile PBS) or chimeric 10G5 are shown. Error bars represent standard error of the mean (SEM). Statistical analysis was performed using two-way ANOVA. *, P<0.05; **, P<0.01; ****, P<0.0001.

FIG. 16

Data from Example 16. The antibody Glymax-c10G5 significantly attenuated growth of A549 tumours compared with the c10G5 (P<0.0001, as determined by two-way ANOVA). The significant difference in activity of wt and defucosylated versions of the chimeric 10G5 indicates importance of antibody-dependent cellular cytotoxicity (ADCC) in inhibition of tumor growth.

FIG. 17

Data from Example 17. The FV1 antibody significantly attenuated growth of A549 tumours compared with the control (P<0.051, as determined by two-way ANOVA); around 25% inhibition was observed after two weeks of treatment.

FIG. 18

Data from Example 18. The FV2 antibody showed moderate anti-tumor activity, similar to the anti-tumor effect of the Anti-EGFR therapeutic antibody cetuximab (Erbitux). Combination of both antibodies resulted in significant tumor growth retardation (P<0.0001; as determined by two-way ANOVA) when compared to isotype control treated animals. The combined effect was also significant when compared to the groups treated with either FV2 or Erbitux alone (P<0.05; as determined by two-way ANOVA).

DISCLOSURE OF THE INVENTION

This invention provides antibodies that bind to Axl protein and inhibits the binding of Axl to its ligand Gas6. The antibodies preferably also downregulate Axl expression, inhibit Axl receptor signalling, and/or inhibit tumour growth.

Disclosed herein are two specific examples of such antibodies that bind Axl and inhibit the binding of Axl to its ligand Gas6. These antibodies are referred to herein as “10C9” (obtainable from hybridoma UT-10C9-B9, as described herein) and “10G5” (obtainable from hybridoma WR-10G5-E5, as described herein).

Accordingly, the present invention provides an antibody that binds to the epitope bound by the 10C9 antibody obtainable from the hybridoma UT-10C9-B9, as described herein. Also provided is an antibody that binds to the epitope bound by the 10G5 antibody obtainable from the hybridoma WR-10G5-E5, as described herein.

Preferably the antibody inhibits the binding of Axl to its ligand Gas6. Even more preferably, the antibody also downregulates Axl expression, inhibits Axl receptor signalling, and/or inhibits tumour growth.

Sequences

The following sequences are disclosed herein (see ‘SEQUENCES’ section below for full sequence):

-   -   SEQ ID NO.1 10C9 VH encoding nucleotide sequence     -   SEQ ID NO.2 10C9 VL encoding nucleotide sequence     -   SEQ ID NO.3 10C9 VH encoding amino acid sequence     -   SEQ ID NO.4 10C9 VL encoding amino acid sequence     -   SEQ ID NO.5 10C9 VH CDR1 encoding amino acid sequence     -   SEQ ID NO.6 10C9 VH CDR2 encoding amino acid sequence     -   SEQ ID NO.7 10C9 VH CDR3 encoding amino acid sequence     -   SEQ ID NO.8 10C9 VL CDR1 encoding amino acid sequence     -   SEQ ID NO.9 10C9 VL CDR2 encoding amino acid sequence     -   SEQ ID NO.10→10C9 VL CDR3 encoding amino acid sequence     -   SEQ ID NO.11→10C9 VH FR1 encoding amino acid sequence     -   SEQ ID NO.12→10C9 VH FR2 encoding amino acid sequence     -   SEQ ID NO.13→10C9 VH FR3 encoding amino acid sequence     -   SEQ ID NO.14→10C9 VH FR4 encoding amino acid sequence     -   SEQ ID NO.15→10C9 VL FR1 encoding amino acid sequence     -   SEQ ID NO.16→10C9 VL FR2 encoding amino acid sequence     -   SEQ ID NO.17→10C9 VL FR3 encoding amino acid sequence     -   SEQ ID NO.18→10C9 VL FR4 encoding amino acid sequence     -   SEQ ID NO.19→10G5 VH encoding nucleotide sequence     -   SEQ ID NO.20→10G5 VL encoding nucleotide sequence     -   SEQ ID NO.21→10G5 VH encoding amino acid sequence     -   SEQ ID NO.22→10G5 VL encoding amino acid sequence     -   SEQ ID NO.23→10G5 VH CDR1 encoding amino acid sequence     -   SEQ ID NO.24→10G5 VH CDR2 encoding amino acid sequence     -   SEQ ID NO.25→10G5 VH CDR3 encoding amino acid sequence     -   SEQ ID NO.26→10G5 VL CDR1 encoding amino acid sequence     -   SEQ ID NO.27→10G5 VL CDR2 encoding amino acid sequence     -   SEQ ID NO.28→10G5 VL CDR3 encoding amino acid sequence     -   SEQ ID NO.29→10G5 VH FR1 encoding amino acid sequence     -   SEQ ID NO.30→10G5 VH FR2 encoding amino acid sequence     -   SEQ ID NO.31→10G5 VH FR3 encoding amino acid sequence     -   SEQ ID NO.32→10G5 VH FR4 encoding amino acid sequence     -   SEQ ID NO.33→10G5 VL FR1 encoding amino acid sequence     -   SEQ ID NO.34→10G5 VL FR2 encoding amino acid sequence     -   SEQ ID NO.35→10G5 VL FR3 encoding amino acid sequence     -   SEQ ID NO.36→10G5 VL FR4 encoding amino acid sequence     -   SEQ ID NO.37→Human Axl encoding amino acid sequence     -   SEQ ID NO.38→Murine Axl encoding amino acid sequence     -   SEQ ID NO.39→Human Tyro3 encoding amino acid sequence     -   SEQ ID NO.40→Human Mer encoding amino acid sequence     -   SEQ ID NO.41→Human Akt3 encoding amino acid sequence     -   SEQ ID NO.42→Human Gas6 encoding amino acid sequence     -   SEQ ID NO.43→‘Cyno-Axi’ encoding amino acid sequence     -   SEQ ID NO.44→Linker     -   SEQ ID NO.45→10G5[Q1E] VH encoding amino acid sequence

The 10C9 Antibody

In one aspect, the present invention provides an isolated antibody that binds Axl and that comprises the 10C9 VH domain (SEQ ID NO: 3) and/or the 10C9 VL domain (SEQ ID NO: 4). Preferably the bound Axl is human Axl.

In one aspect, the present invention provides an isolated antibody that binds Axl and that comprises the 10G5 VH domain (SEQ ID NO: 21) and/or the 10G5 VL domain (SEQ ID NO: 22). Preferably the bound Axl is human Axl. In an alternative non-preferred aspect, the present invention provides an isolated antibody that binds Axl and that comprises the 10G5[Q1E] VH domain (SEQ ID NO: 45) and/or the 10G5 VL domain (SEQ ID NO: 22). Preferably the bound Axl is human Axl.

Generally, a VH domain is paired with a VL domain to provide an antibody antigen binding site, although as discussed further below a VH domain alone may be used to bind antigen. In one preferred embodiment, the 10C9 VH domain (SEQ ID NO: 3) is paired with the 10C9 VL domain (SEQ ID NO: 4), so that an antibody antigen binding site is formed comprising both the 10C9 VH and VL domains.

In other embodiments, the 10C9 VH is paired with a VL domain other than the 10C9 VL; light-chain promiscuity is well established in the art. For example, in some embodiments the 10C9 VH domain (SEQ ID NO: 3) is paired with the 10G5 VL domain (SEQ ID NO: 22).

One or more CDR's may be taken from the 10C9 VH or VL domain and incorporated into a suitable framework. This is discussed further below. 10C9 VH CDR's 1, 2 and 3 are shown in SEQ ID Nos 5, 6 and 7, respectively. 10C9 VL CDR's 1, 2 and 3 are shown in SEQ ID Nos 8, 9, and 10, respectively.

In one aspect of the invention there is provided an antibody that binds Axl and that comprises:

-   -   an antibody VH domain selected from the group consisting of the         10C9 VH domain (SEQ ID NO.3) and a VH domain comprising a VH         CDR3 with the amino acid sequence of SEQ ID NO.7 and optionally         one or more VH CDR's with an amino acid sequence selected from         SEQ ID NO.6 and SEQ ID NO.5; and/or     -   an antibody VL domain selected from the group consisting of the         10C9 VL domain (SEQ ID NO. 4) and a VL domain comprising one or         more VL CDR's with an amino acid sequence selected from SEQ ID         NO.8, SEQ ID NO.9 and SEQ ID NO.10.

For example, the antibody may comprise an antibody VH domain comprising the VH CDR's with the amino acid sequences of SEQ ID NO.5, SEQ ID NO.6 and SEQ ID NO.7. The antibody may further comprise an antibody VL domain comprising the VL CDR's with the amino acid sequences of SEQ ID NO.8, SEQ ID NO.9 and SEQ ID NO.10.

In some embodiments the antibody comprises: (i) an antibody VH domain comprising the VH CDR's with the amino acid sequences of SEQ ID NO.5, SEQ ID NO.6 and SEQ ID NO.7, and (ii) an antibody VL domain comprising the VL CDR's with the amino acid sequences of SEQ ID NO.8, SEQ ID NO.9 and SEQ ID NO.10.

The antibody may comprise the 10C9 VH domain (SEQ ID NO. 3) and, optionally, further comprise the 10C9 VL domain (SEQ ID NO. 4)

Preferably the antibody competes for binding to human Axl with an Axl binding domain of an antibody comprising the 10C9 VH domain (SEQ ID NO. 3) and the 10C9 VL domain (SEQ ID NO. 4).

Preferably the antibody binds to the epitope bound by the antibody obtainable from the hybridoma UT-10C9-B9, as described herein.

Preferably the antibody inhibits the binding of Axl to its ligand Gas6. Even more preferably, the antibody also downregulates Axl expression, inhibits Axl receptor signalling, and/or inhibits tumour growth.

According to a further aspect of the invention, there are provided variants of the VH and VL domains of which the sequences are set out herein and that can be employed in antibodies for Axl and can be obtained by means of methods of sequence alteration or mutation and screening. Such methods are also provided by the present invention.

Variable domain amino acid sequence variants of any of the VH and VL domains whose sequences are specifically disclosed herein may be employed in accordance with the present invention, as discussed. Particular variants may include one or more amino acid sequence alterations (addition, deletion, substitution and/or insertion of an amino acid residue), maybe less than about 20 alterations, less than about 15 alterations, less than about 10 alterations or less than about 5 alterations, 4, 3, 2 or 1. Alterations may be made in one or more framework regions and/or one or more CDR's.

An antibody according to the invention may be one that competes for binding to antigen with any antibody that both binds the antigen and comprises an antibody VH and/or VL domain disclosed herein, or VH CDR3 disclosed herein, or variant of any of these. Competition between antibody may be assayed easily in vitro, for example using ELISA and/or by tagging a specific reporter molecule to one antibody that can be detected in the presence of other untagged antibody(s), to enable identification of antibodies that bind the same epitope or an overlapping epitope.

Accordingly, the present invention comprises a variant of any antibody specifically disclosed herein, wherein the variant comprises one or more amino acid sequence alterations in one or more framework regions and/or one or more CDRs. For example, the variant antibody may comprise no more than 4 sequence alterations in any one CDR, such as no more than 3, no more than 2, no more than 1 sequence alterations, or no sequence alterations in any one CDR (such as CDR3 of the VH domain). The variant antibody may compete for binding to Axl (for example, human Axl) with an Axl binding domain of an antibody comprising the 10C9 VH domain (SEQ ID NO. 3) and the 10C9 VL domain (SEQ ID NO. 4).

Thus a further aspect of the present invention provides an antibody comprising a human antibody antigen-binding site that competes with 10C9 for binding to human Axl.

In one aspect the present invention provides the antibody obtainable from the hybridoma UT-10C9-B9, as described herein.

Various methods are available in the art for obtaining antibodies against Axl and which may compete with 10C9 for binding to Axl.

In a further aspect, the present invention provides a method of obtaining one or more antibodies able to bind the antigen, the method including bringing into contact a library of antibodies according to the invention and said antigen, and selecting one or more antibody members of the library able to bind said antigen.

The library may be displayed on the surface of bacteriophage particles, each particle containing nucleic acid encoding the antibody VH variable domain displayed on its surface, and optionally also a displayed VL domain if present.

Following selection of antibodies able to bind the antigen and displayed on bacteriophage particles, nucleic acid may be taken from a bacteriophage particle displaying a said selected antibody. Such nucleic acid may be used in subsequent production of an antibody or an antibody VH variable domain (optionally an antibody VL variable domain) by expression from nucleic acid with the sequence of nucleic acid taken from a bacteriophage particle displaying a said selected antibody.

An antibody VH variable domain with the amino acid sequence of an antibody VH variable domain of a said selected antibody may be provided in isolated form, as may an antibody comprising such a VH domain.

Ability to bind Axl may be further tested, also ability to compete with 10C9 for binding to Axl.

Alternatively, to screen for antibodies that bind to the epitope on Axl bound by an antibody of interest (e.g., those which block binding of the 10C9 or 10G5 antibody to Axl), a routine cross-blocking assay such as that described in Antibodies. A Laboratory Manual. Cold Spring Harbor Laboratory. Ed Harlow and David Lane (1988), can be performed.

An antibody according to the present invention may bind Axl with the affinity of 10C9.

An antibody of the invention may bind to murine, rat, monkey, non-human primate and/or human Axl. Preferably, the antibody binds to human and monkey Axl. In some embodyments the antibody specifically binds primate Axl. For example, the antibody may specifically bind human and monkey Axl. In one embodiment the antibody specifically binds only human Axl.

The antibody may be a chimeric, humanised, or CDR-grafted anti-Axl antibody. For example, the antibody may be a chimeric human/mouse antibody.

Binding affinity and neutralisation potency of different antibodies can be compared under appropriate conditions.

In addition to antibody sequences, an antibody according to the present invention may comprise other amino acids, e.g. forming a peptide or polypeptide, such as a folded domain, or to impart to the molecule another functional characteristic in addition to ability to bind antigen.

Antibodies of the invention may carry a detectable label, or may be conjugated to a toxin (such as a cytotoxin), enzyme, or an organic moiety (e.g. via a peptidyl bond or linker).

Those skilled in the art are aware of numerous approaches to chemically conjugating molecules to proteins. In one embodiment of the present invention, the antibody can be conjugated to a detectable, fluorescent label, e.g. fluorescein isothiocyanate (FITC), or to a reporter enzyme such as horseradish peroxidase (HRP)

In a preferred embodiment, the antibody is conjugated to a cytotoxic drug with a formation of the antibody-drug conjugate (ADC). When the antibody is for pharmaceutical use, the bond linking the antibody and drug is preferably stable in circulation (for example, blood circulation) but labile once the conjugate is sequestered intracellularly. Thus, the antibody conjugated as an immunoconjugate may be used in a method of treatment of, for example, cancer.

In further aspects, the invention provides an isolated nucleic acid that comprises a sequence encoding an antibody, VH domain and/or VL domain according to the present invention, and methods of preparing an antibody, a VH domain and/or a VL domain of the invention, that comprise expressing said nucleic acid under conditions to bring about production of said antibody, VH domain and/or VL domain, and recovering it.

Antibodies according to the invention may be used in a method of treatment or diagnosis of the human or animal body, such as a method of treatment (which may include prophylactic treatment) of a disease or disorder in a human patient that comprises administering to said patient an effective amount of an antibody of the invention, or a conjugate, or drug-conjugate thereof. Conditions treatable in accordance with the present invention include those discussed elsewhere herein.

Antibodies according to the invention may be used in a method of imaging, for example, to determine the presence or location of cells to which the antibody binds.

In a further aspect, the present invention provides a diagnostic kit comprising an antibody according to the invention and one or more reagents to determine binding of the antibody to the antigen.

A further aspect of the present invention provides nucleic acid, generally isolated, encoding an antibody VH variable domain (SEQ ID NO: 3) and/or VL variable domain (SEQ ID NO: 4) disclosed herein. In some embodiments the VH encoding nucleic acid has the sequence set out in SEQ ID NO: 1. In some embodiments the VL encoding nucleic acid has the sequence set out in SEQ ID NO: 2.

Another aspect of the present invention provides nucleic acid, generally isolated, encoding a VH CDR or VL CDR sequence disclosed herein, especially a VH CDR selected from SEQ ID NOs 5, 6, and 7 or a VL CDR selected from SEQ ID NOs 8, 9, or 10, most preferably 10C9 CDR3 (SEQ ID NO: 7).

A further aspect provides a host cell transformed with nucleic acid of the invention.

A yet further aspect provides a method of production of an antibody VH variable domain, the method including causing expression from encoding nucleic acid. Such a method may comprise culturing host cells under conditions for production of said antibody VH variable domain.

Analogous methods for production of VL variable domains and antibodies comprising a VH and/or VL domain are provided as further aspects of the present invention.

A method of production may comprise a step of isolation and/or purification of the product.

A method of production may comprise formulating the product into a composition including at least one additional component, such as a pharmaceutically acceptable excipient.

These and other aspects of the invention are described in further detail below.

The 10G5 Antibody

In one aspect, the present invention provides an isolated antibody that binds Axl and that comprises the 10G5 VH domain (SEQ ID NO: 21) and/or the 10G5 VL domain (SEQ ID NO: 22). Preferably the bound Axl is human Axl. In an alternative non-preferred aspect, the present invention provides an isolated antibody that binds Axl and that comprises the 10G5[Q1E] VH domain (SEQ ID NO: 45) and/or the 10G5 VL domain (SEQ ID NO: 22). Preferably the bound Axl is human Axl.

In a preferred embodiment, the 10G5 VH domain (SEQ ID NO: 21) is paired with the 10G5 VL domain (SEQ ID NO: 22), so that an antibody antigen binding site is formed comprising both the 10G5 VH and VL domains. In other embodiments, the 10G5 VH is paired with a VL domain other than the 10G5 VL; light-chain promiscuity is well established in the art. For example, in some embodiments the 10G5 VH domain (SEQ ID NO: 21) is paired with the 10C9 VL domain (SEQ ID NO: 4). In an alternative non-preferred aspect, the 10G5[Q1E] VH domain (SEQ ID NO: 45) is paired with the 10G5 VL domain (SEQ ID NO: 22), so that an antibody antigen binding site is formed comprising both the 10G5 VH and VL domains. In other embodiments, the 10G5 VH is paired with a VL domain other than the 10G5 VL; light-chain promiscuity is well established in the art. For example, in some embodiments the 10G5[Q1E] VH domain (SEQ ID NO: 45) is paired with the 10C9 VL domain (SEQ ID NO: 4).

One or more CDR's may be taken from the 10G5 VH or VL domain and incorporated into a suitable framework. This is discussed further below. 10G5 VH CDR's 1, 2 and 3 are shown in SEQ ID Nos 23, 24 and 25, respectively. 10G5 VL CDR's 1, 2 and 3 are shown in SEQ ID Nos 26, 27, and 28, respectively.

In one aspect of the invention there is provided an antibody that binds Axl and that comprises:

-   -   an antibody VH domain selected from the group consisting of the         10G5 VH domain (SEQ ID NO.21), the 10G5[Q1E] VH domain (SEQ ID         NO: 45), and a VH domain comprising a VH CDR3 with the amino         acid sequence of SEQ ID NO.25 and optionally one or more VH         CDR's with an amino acid sequence selected from SEQ ID NO.24 and         SEQ ID NO.23; and/or     -   an antibody VL domain selected from the group consisting of the         10G5 VL domain (SEQ ID NO. 22) and a VL domain comprising one or         more VL CDR's with an amino acid sequence selected from SEQ ID         NO.26, SEQ ID NO.27 and SEQ ID NO.28.

For example, the antibody may comprise an antibody VH domain comprising the VH CDR's with the amino acid sequences of SEQ ID NO.23, SEQ ID NO.24 and SEQ ID NO.25. The antibody may further comprise an antibody VL domain comprising the VL CDR's with the amino acid sequences of SEQ ID NO.26, SEQ ID NO.27 and SEQ ID NO.28.

In some embodiments the antibody comprises: (i) an antibody VH domain comprising the VH CDR's with the amino acid sequences of SEQ ID NO.23, SEQ ID NO.24 and SEQ ID NO.25, and (ii) an antibody VL domain comprising the VL CDR's with the amino acid sequences of SEQ ID NO.26, SEQ ID NO.27 and SEQ ID NO.28.

The antibody may comprise the 10G5 VH domain (SEQ ID NO. 21) and, optionally, further comprise the 10G5 VL domain (SEQ ID NO. 22). In alternative, non-preferred embodiments, the antibody may comprise the 10G5[Q1E] VH domain (SEQ ID NO: 45), and, optionally, further comprise the 10G5 VL domain (SEQ ID NO. 22).

Preferably the antibody competes for binding to human Axl with an Axl binding domain of an antibody comprising the 10G5 VH domain (SEQ ID NO. 21) and the 10G5 VL domain (SEQ ID NO. 22).

Preferably the antibody binds to the epitope bound by the antibody obtainable from the hybridoma WR-10G5-E5, as described herein.

Preferably the antibody inhibits the binding of Axl to its ligand Gas6. Even more preferably, the antibody also downregulates Axl expression, inhibits Axl receptor signalling, and/or inhibits tumour growth.

According to a further aspect of the invention, there are provided variants of the VH and VL domains of which the sequences are set out herein and which can be employed in antibodies for Axl and can be obtained by means of methods of sequence alteration or mutation and screening. Such methods are also provided by the present invention.

Variable domain amino acid sequence variants of any of the VH and VL domains whose sequences are specifically disclosed herein may be employed in accordance with the present invention, as discussed. Particular variants may include one or more amino acid sequence alterations (addition, deletion, substitution and/or insertion of an amino acid residue), maybe less than about 20 alterations, less than about 15 alterations, less than about 10 alterations or less than about 5 alterations, 4, 3, 2 or 1. Alterations may be made in one or more framework regions and/or one or more CDR's.

An antibody according to the invention may be one that competes for binding to antigen with any antibody that both binds the antigen and comprises an antibody VH and/or VL domain disclosed herein, or VH CDR3 disclosed herein, or variant of any of these. Competition between antibody may be assayed easily in vitro, for example using ELISA and/or by tagging a specific reporter molecule to one antibody that can be detected in the presence of other untagged antibody(s), to enable identification of antibodies that bind the same epitope or an overlapping epitope.

Alternatively, to screen for antibodies that bind to the epitope on Axl bound by an antibody of interest (e.g., those that block binding of the 10C9 or 10G5 antibody to Axl), a routine cross-blocking assay such as that described in Antibodies. A Laboratory Manual. Cold Spring Harbor Laboratory. Ed Harlow and David Lane (1988), can be performed.

Accordingly, the present invention comprises a variant of any antibody specifically disclosed herein, wherein the variant comprises one or more amino acid sequence alterations in one or more framework regions and/or one or more CDRs. For example, the variant antibody may comprise no more than 4 sequence alterations in any one CDR, such as no more than 3, no more than 2, no more than 1 sequence alterations, or no sequence alterations in any one CDR (such as CDR3 of the VH domain). The variant antibody may compete for binding to Axl (for example, human Axl) with an Axl binding domain of an antibody comprising the 10G5 VH domain (SEQ ID NO. 21) and the 10G5 VL domain (SEQ ID NO. 22).

Thus a further aspect of the present invention provides an antibody comprising a human antibody antigen-binding site that competes with 10G5 for binding to human Axl.

In one aspect the present invention provides the antibody obtainable from the hybridoma WR-10G5-E5, as described herein.

Various methods are available in the art for obtaining antibodies against Axl and that may compete with 10G5 for binding to Axl.

In a further aspect, the present invention provides a method of obtaining one or more antibodies able to bind the antigen, the method including bringing into contact a library of antibodies according to the invention and said antigen, and selecting one or more antibody members of the library able to bind said antigen.

The library may be displayed on the surface of bacteriophage particles, each particle containing nucleic acid encoding the antibody VH variable domain displayed on its surface, and optionally also a displayed VL domain if present.

Following selection of antibodies able to bind the antigen and displayed on bacteriophage particles, nucleic acid may be taken from a bacteriophage particle displaying a said selected antibody. Such nucleic acid may be used in subsequent production of an antibody or an antibody VH variable domain (optionally an antibody VL variable domain) by expression from nucleic acid with the sequence of nucleic acid taken from a bacteriophage particle displaying a said selected antibody.

An antibody VH variable domain with the amino acid sequence of an antibody VH variable domain of a said selected antibody may be provided in isolated form, as may an antibody comprising such a VH domain.

Ability to bind Axl may be further tested, also ability to compete with 10G5 for binding to Axl.

An antibody according to the present invention may bind Axl with the affinity of 10G5.

An antibody of the invention may bind to murine, rat, monkey, non-human primate and/or human Axl. Preferably, the antibody binds to human and monkey Axl. In some embodiments the antibody specifically binds primate Axl. For example, the antibody may specifically bind human and monkey Axl. In one embodiment the antibody specifically binds only human Axl.

The antibody may be a chimeric, humanised, or CDR-grafted anti-Axl antibody. For example, the antibody may be a chimeric human/mouse antibody.

Binding affinity and neutralisation potency of different antibodies can be compared under appropriate conditions.

In addition to antibody sequences, an antibody according to the present invention may comprise other amino acids, e.g. forming a peptide or polypeptide, such as a folded domain, or to impart to the molecule another functional characteristic in addition to ability to bind antigen.

Antibodies of the invention may carry a detectable label, or may be conjugated to a toxin (such as a cytotoxin), enzyme, or an organic moiety (e.g. via a peptidyl bond or linker).

Those skilled in the art are aware of numerous approaches to chemically conjugating molecules to proteins. In one embodiment of the present invention, the antibody can be conjugated to a detectable, fluorescent label, e.g. fluorescein isothiocyanate (FITC), or to a reporter enzyme such as horseradish peroxidase (HRP)

In a preferred embodiment, the antibody is conjugated to a cytotoxic drug with a formation of the antibody-drug conjugate (ADC). When the antibody is for pharmaceutical use, the bond linking the antibody and drug is preferably stable in circulation (for example, blood circulation) but labile once the conjugate is sequestered intracellularly. Thus, the antibody conjugated as an immunoconjugate may be used in a method of treatment of, for example, cancer.

In further aspects, the invention provides an isolated nucleic acid that comprises a sequence encoding an antibody, VH domain and/or VL domain according to the present invention, and methods of preparing an antibody, a VH domain and/or a VL domain of the invention, that comprise expressing said nucleic acid under conditions to bring about production of said antibody, VH domain and/or VL domain, and recovering it.

Antibodies according to the invention may be used in a method of treatment or diagnosis of the human or animal body, such as a method of treatment (that may include prophylactic treatment) of a disease or disorder in a human patient that comprises administering to said patient an effective amount of an antibody of the invention, or a conjugate, or drug-conjugate thereof. Conditions treatable in accordance with the present invention include those discussed elsewhere herein.

Antibodies according to the invention may be used in a method of imaging, for example, to determine the presence or location of cells to which the antibody binds.

In a further aspect, the present invention provides a diagnostic kit comprising an antibody according to the invention and one or more reagents to determine binding of the antibody to the antigen.

A further aspect of the present invention provides nucleic acid, generally isolated, encoding an antibody VH variable domain (SEQ ID NO: 21), an antibody VH variable domain (SEQ ID NO: 45), and/or VL variable domain (SEQ ID NO: 22) disclosed herein. In some embodiments the VH encoding nucleic acid has the sequence set out in SEQ ID NO: 19. In some embodiments the VL encoding nucleic acid has the sequence set out in SEQ ID NO: 20.

Another aspect of the present invention provides nucleic acid, generally isolated, encoding a VH CDR or VL CDR sequence disclosed herein, especially a VH CDR selected from SEQ ID NOs 23, 24, and 25 or a VL CDR selected from SEQ ID NOs 26, 27, or 28, most preferably 10G5 CDR3 (SEQ ID NO: 25).

A further aspect provides a host cell transformed with nucleic acid of the invention.

A yet further aspect provides a method of production of an antibody VH variable domain, the method including causing expression from encoding nucleic acid. Such a method may comprise culturing host cells under conditions for production of said antibody VH variable domain.

Analogous methods for production of VL variable domains and antibodies comprising a VH and/or VL domain are provided as further aspects of the present invention.

A method of production may comprise a step of isolation and/or purification of the product.

A method of production may comprise formulating the product into a composition including at least one additional component, such as a pharmaceutically acceptable excipient.

These and other aspects of the invention are described in further detail below.

Properties of the 10C9 Antibody

High affinity for Axl

The 10C9 antibody described herein binds to human Axl with high affinity. As described in Examples 5 and 13, the murine 10C9 antibody was determined to have a K_(D) of 0.18 nM whilst the chimeric version was determined to have a K_(D) of 0.10 nM.

Accordingly, the 10C9 antibodies and variant thereof that are described herein bind Axl with high affinity; preferably human Axl is bound with high affinity. In some embodiments, an antibody binds to Axl (or human Axl) with a K_(D) no greater than 10⁻⁶ M, such as no greater than 5×10⁻⁷ M, no greater than 10⁻⁷ M, no greater than 5×10⁻⁸ M, no greater than 10⁻⁸ M, no greater than 5×10⁻⁹ M, no greater than 10⁻⁹ M, no greater than 5×10⁻¹⁰ M, no greater than 2×10⁻¹⁰ M, no greater than 1.1×10⁻¹⁰ M, no greater than 10⁻¹⁰ M, no greater than 5×10⁻¹¹ M, no greater than 10⁻¹¹ M, no greater than 5×10⁻¹² M, no greater than 6×10⁻¹² M, no greater than 10⁻¹² M, no greater than 5×10⁻¹³ M, no greater than 10⁻¹³ M, no greater than 5×10⁻¹⁴ M, no greater than 10⁻¹⁴ M, no greater than 5×10⁻¹⁵ M, or no greater than 10⁻¹⁵ M.

In some embodiments, an antibody binds to Axl (or human Axl) with a K_(D) from 10⁻⁸ M to 10⁻¹⁰ M, from 10⁻¹⁰ M to 10⁻¹², from 10⁻¹² M to 10⁻¹⁴, or from 10⁻¹⁴ M to 10⁻¹⁶.

The K_(D) may be determined and calculated as set out in Example 5, or Example 13.

The 10C9 antibody described herein is characterized by having a very fast association rate (k_(on)). Specifically, in Example 5 the murine 10C9 antibodies was determined to have the very fast association rate of k_(on)=1.61×10⁶ M⁻¹s⁻¹, whilst in Example 13 the chimeric 10C9 antibodies was determined to have the even faster association rate of k_(on)=2.16×10⁶ M⁻¹s⁻¹. Accordingly, the antibodies described herein preferably bind human Axl with a fast association rate. In some embodiments, an antibody binds to Axl (or human Axl) with a k_(on) no lower than 10⁴ M⁻¹s⁻¹, such as no lower than 5×10⁴ M⁻¹s⁻¹, no lower than 10⁵ M⁻¹s⁻¹, no lower than 5×10⁵ M⁻¹s⁻¹, no lower than 10⁶ M⁻¹s⁻¹, no lower than 1.5×10⁶ M⁻¹s⁻¹, no lower than 2×10⁶ M⁻¹s⁻¹, no lower than 5×10⁶ M⁻¹s⁻¹, no lower than 10⁷ M⁻¹s⁻¹, no lower than 2×10⁷ M⁻¹s⁻¹, no lower than 5×10⁷ M⁻¹s⁻¹, no lower than 10⁸ M⁻¹s⁻¹, no lower than 5×10⁸ M⁻¹s⁻¹, or no lower than 10⁹ M⁻¹s⁻¹.

Properties of the 10G5 Antibody High Affinity for Axl

The 10G5 antibody described herein binds to human Axl with high affinity. As described in Examples 5 and 13, the murine 10G5 antibody was determined to have a K_(D) of 0.53 nM whilst the chimeric version was determined to have a K_(D) of 0.10 nM.

Accordingly, the 10G5 antibodies and variant thereof that are described herein bind Axl with high affinity; preferably human Axl is bound with high affinity. In some embodiments, an antibody binds to Axl (or human Axl) with a K_(D) no greater than 10⁻⁶ M, such as no greater than 5×10⁻⁷ M, no greater than 10⁻⁷ M, no greater than 5×10⁻⁸ M, no greater than 10⁻⁸ M, no greater than 5×10⁻⁹ M, no greater than 10⁻⁹ M, no greater than 6×10⁻¹⁰ M, no greater than 5×10⁻¹⁰ M, no greater than 1.1×10⁻¹⁰ M, no greater than 10⁻¹⁰ M, no greater than 5×10⁻¹¹ M, no greater than 10⁻¹¹ M, no greater than 5×10⁻¹² M, no greater than 6×10⁻¹² M, no greater than 10⁻¹² M, no greater than 5×10⁻¹³ M, no greater than 10⁻¹³ M, no greater than 5×10⁻¹⁴ M, no greater than 10⁻¹⁴ M, no greater than 5×10⁻¹⁵ M, or no greater than 10⁻¹⁵ M.

In some embodiments, an antibody binds to Axl (or human Axl) with a K_(D) from 10⁻⁸ M to 10⁻¹⁰ M, from 10⁻¹⁰ M to 10⁻¹², from 10⁻¹² M to 10⁻¹⁴, or from 10⁻¹⁴ M to 10⁻¹⁶.

The K_(D) may be determined and calculated as set out in Example 5, or Example 13.

The 10G5 antibody described herein is characterized by having a very fast association rate (k_(on)). Specifically, in Example 5 the murine 10G5 antibodies was determined to have the very fast association rate of k_(on)=0.83×10⁶ M⁻¹s⁻¹, whilst in Example 13 the chimeric 10C9 antibodies was determined to have the even faster association rate of k_(on)=1.64×10⁶ M⁻¹s⁻¹. Accordingly, the antibodies described herein preferably bind human Axl with a fast association rate. In some embodiments, an antibody binds to Axl (or human Axl) with a k_(on) no lower than 10⁴ M⁻¹s⁻¹, such as no lower than 5×10⁴ M⁻¹s⁻¹, no lower than 10⁵ M⁻¹s⁻¹, no lower than 5×10⁵ M⁻¹s⁻¹, no lower than 10⁶ M⁻¹s⁻¹, no lower than 1.5×10⁶ M⁻¹s⁻¹, no lower than 2×10⁶ M⁻¹s⁻¹, no lower than 5×10⁶ M⁻¹s⁻¹, no lower than 10⁷ M⁻¹s⁻¹, no lower than 2×10⁷ M⁻¹s⁻¹, no lower than 5×10⁷ M⁻¹s⁻¹, no lower than 10⁸ M⁻¹s⁻¹, no lower than 5×10⁸ M⁻¹s⁻¹, or no lower than 10⁹ M⁻¹s⁻¹.

Properties of Both the 10C9 & 10G5 Antibodies Specific Binding

Generally, the terms ‘specific’ and ‘specifically binds’ may be used to refer to the situation in which an antibody will not show any significant binding to molecules other than its specific binding partner(s). For example, an antibody that ‘specifically binds’ human Axl would not show any significant binding for murine Axl.

The term is also applicable where e.g. an antibody is specific for a particular epitope that is carried by a number of antigens, in which case an antibody that ‘specifically binds’ an epitope will be able to bind to all of the various antigens that carry the recognised epitope.

Typically, specificity may be determined by means of a binding assay such as ELISA employing a panel of antigens.

The 10C9 and 10G5 antibodies described herein bind to human Axl with high specificity. That is, the 10C9 and 10G5 antibodies ‘specifically bind’ human Axl. This is demonstrated in the examples, where it is shown that:

-   -   (1) In Example 2, 10C9 and 10G5 show no significant binding to         recombinant antigens derived from hMer and hTyro3, the other         members of the human TAM receptor tyrosine kinase family;     -   (2) In Example 3, 10C9 and 10G5 bind strongly to human Axl, but         show no binding to murine Axl (this is in contrast to murine Axl         ligand, murine Gas 6, that binds strongly to both murine and         human Axl, as well as (more weakly) binding human Tyro3);     -   (3) In Example 4, 10C9 and 10G5 bind strongly to Axl from the         cynomolgus monkey (Macaca fascicularis).

Accordingly, the antibodies described herein preferably specifically bind primate Axl. In some embodiments the antibodies described herein specifically bind human and monkey (such as Macaca fascicularis) Axl. In one embodiment the antibodies specifically bind only human Axl.

In some embodiments of the present invention, the antibodies described herein show no significant binding to human Tyro3 and/or human Mer. In some embodiments the antibodies described herein show no significant binding to murine Axl. In some embodiments the antibodies described herein show no significant binding to any of human Tyro3, human Mer, or murine Axl.

Whether an antibody shows “no significant binding” to an antigen can be readily determined by the skilled person using, for example, the techniques described in Examples 2 and 3. In some embodiments, an antibody is deemed to show “no significant binding” to a particular antigen if it binds the antigen with a K_(D) greater than 10⁻³ M, such as greater than 10⁻² M, greater than 10⁻¹ M, or greater than 1 M. The K_(D) may be determined and calculated as set out in Example 5.

Inhibition of Axl/Gas6 Binding

The 10C9 and 10G5 antibodies described herein inhibit the binding of Axl to its ligand Gas6.

FIG. 5 shows the results of the competitive binding assay described in Example 6. The results show that immobilised rhAxl saturated with 10C9 cannot be bound by subsequently added 10C9, or any of 10G5, rhGas6 (a known ligand of rhAxl), or rmGas6. This indicates that the areas of the Axl molecule bound by 10C9, 10G5 and Gas6 are in close proximity to one another. In contrast, the binding of 10C9 did no inhibit the binding of the MAB154 anti-Axl antibody, indicating that 10C9 and MAB154 bind to distinct parts of the Axl molecule.

Accordingly, in preferred embodiments the antibodies described herein inhibit the binding of Axl to Gas6 (for example, rhAxl to rhGas6). That is, preferably the antibodies described herein compete with human Gas 6 for binding to human Axl. Most preferably, inhibition of Axl/Gas 6 binding is such that no significant binding of Gas6 can be observed to an Axl sample saturated with the antibody (for example, no more than 1% of the binding observed to an Axl sample that has not been previously exposed to the antibody). Inhibition of Gas 6 binding may be assessed using the competitive binding assay described in Example 6.

Inhibition of Axl Receptor Expression

The antibodies of the invention lead to a significant reduction in the expression of Axl.

FIG. 8 shows the results of the Western Blot analyses described in Example 9, in which MBA-MD-231 cells are incubated overnight with one of a range of antibodies and then tested for Axl expression. The results show that incubation with 10C9 leads to a significant reduction in the amount of Axl receptor protein present in the cell, indicating that binding of the 10C9 antibody downregulates the expression of the Axl receptor.

Accordingly, in preferred embodiments the antibodies of the invention downregulate expression of the Axl receptor.

In some embodiments, the antibody of the invention reduces Axl receptor expression to less than 80% of the level observed in an otherwise identically treated sample that is not contacted with to the antibody. In some embodiments, the antibody of the invention reduces Axl receptor expression to less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, or less than 10% of the level observed in an otherwise identically treated sample that is not contacted with the antibody. The level of Axl receptor expression may be assessed using the assay described in Example 9; a number of methods for accurately quantifying bands on Western blots are known in the art—see, for example, Taylor et al. Mol Biotechnol. 2013; 55(3): 217-226.

In some embodiments down-regulation of Axl receptor expression occurs rapidly; for example, in some embodiments a reduction of Axl receptor expression to less than 80% of the level observed in an otherwise identically treated sample that is not contacted with the antibody is observed within 12 hours of contacting the sample with the antibody, for example within 12 hours, within 6 hours, within 3 hours, or within 1 hour of contacting the sample with the antibody.

In some embodiments, the antibody causes persistent downregulation of Axl receptor expression. For example, in some embodiments the level of Axl receptor expression in a sample contacted with the antibody remains below 50% of the level observed in an otherwise identically treated sample that is not contacted with the antibody for at least 6 hours following contacting the sample with the antibody, such as at least 12 hours, at least 24 hours, at least 48 hours, or at least 96 hours.

Without wishing to be bound by theory, it is believed the observed down-regulation of Axl expression is caused by the antibody/Axl receptor complex being internalised and degraded by the cell. Internalisation of the antibody is highly advantageous for applications where it is desirable to get the antibody, or a molecule linked to the antibody, into a target cell. For example, where the target is a cancerous cell and the antibody is linked to a cytotoxic drug.

Accordingly, in preferred embodiments the antibodies of the invention increases the rate of Axl receptor internalization.

In some embodiments, the antibody of the invention increases the rate of Axl receptor internalization to at least 110% of the level observed in an otherwise identically treated sample that is not contacted with the antibody. In some embodiments, the antibody of the invention increases the rate of Axl receptor internalization to at least 120%, at least 130%, at least 140%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190%, at least 200%, at least 500%, at least 1000% of the level observed in an otherwise identically treated sample that is not contacted with the antibody.

The level of Axl receptor internalization may be assessed using any one of the receptor internalisation assay known in the art; for example, the method described in Koenig et al. Methods in Molecular Biology Volume 259, 2004, pp 249-273.

Inhibition of Axl Receptor Signalling

Consistent with the observations that the antibodies of the invention (1) inhibit the binding of the Axl receptor to natural ligands such as Gas6, and (2) downregulate the expression of the Axl receptor, the antibodies of the invention inhibit ligand-induced signalling downstream of the Axl receptor. This is demonstrated in FIG. 9 , where it can be seen that the presence of the 10C9 antibody significantly reduces the degree to which Akt's Serine 473 is phosphorylated on addition of the Axl ligand Gas6.

Accordingly, in preferred embodiments the antibodies of the invention inhibit Axl activity. The inhibited activity may be constitutive Axl activity.

In some embodiments the antibodies of the invention inhibit Axl downstream signalling, for example the phosphorylation of Akt at Serine 473. In some embodiments, the phosphorylation of Akt at Serine 473 in a sample contacted with the antibody of the invention is less than 80% of the level observed in an otherwise identically treated sample that is not contacted with the antibody. In some embodiments, the phosphorylation of Akt at Serine 473 in a sample contacted with the antibody of the invention is less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, or less than 10% of the level observed in an otherwise identically treated sample that is not contacted with the antibody. The level of phosphorylation of Akt at Serine 473 may be assessed using the assay described in Example 10; a number of methods for accurately quantifying bands on Western blots are known in the art—see, for example, Taylor et al. Mol Biotechnol. 2013; 55(3): 217-226.

By virtue of inhibiting Axl receptor signalling, the antibodies of the invention are also expected to influence a range of processes in which Axl-receptor signalling plays a role.

For example, it is known that Axl-receptor signalling stimulates Gas6 dependent cell proliferation and inhibits cell-death, thus supporting tumour growth. It is also known that Axl receptor signalling stimulates Epithelial-Mesenchymal transition (EMT) and thus promotes tumour metastases.

Accordingly, in some embodiments, the antibodies of the invention promotes cell death, for example by apoptosis. Preferably the cell is a tumour cell, such as a circulating tumour cell or a metastatic cell. For example, in some embodiments, the antibody of the invention increases the rate of cell-death to at least 110% of the level observed in an otherwise identically treated sample that is not contacted with the antibody. In some embodiments, the antibody of the invention increases the rate of cell death to at least 120%, at least 130%, at least 140%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190%, at least 200%, at least 500%, at least 1000% of the level observed in an otherwise identically treated sample that is not exposed to the antibody. The rate of ell death may be measured by, for example BrdU incorporation assay, MTT, [³H]-thymidine incorporation (e.g., TopCount assay (PerkinElmer)), cell viability assays (e.g., CellTiter-Glo (Promega)), DNA fragmentation assays, caspase activation assays, tryptan blue exclusion, chromatin morphology assays and the like.

In some embodiments, the antibodies of the invention inhibit Axl downstream signalling. In some embodiments, the antibodies of the invention inhibit Gas6 dependent cell proliferation.

In some embodiments, the antibodies of the invention inhibit inflammatory cytokine expression from tumour-associated macrophages.

Inhibition of Tumour Growth

Consistent with the role of Axl and the EMT pathway in tumour growth, the antibodies of the invention reduce the rate of growth of both haematological and non-heamatological tumours; this is demonstrated by the data shown in FIGS. 14 and 15 , as obtained through the methods described ibn Examples 14 and 15.

Accordingly, in preferred embodiments the antibodies of the invention inhibit tumour growth and/or metastasis by, for example, modulating tumour stromal function.

In some embodiments the antibodies of the invention inhibit tumour growth by at least 10% compared to a control tumour. That is, the volume of the antibody treated tumour is no more than 90% of the volume of the control tumour. For example, in some embodiments the antibodies of the invention inhibit tumour growth by at least 20% compared to a control tumour, such as at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%.

In some embodiments, the effect of the antibody on tumour growth is assayed as described in example 14. In some embodiments, the effect of the antibody on tumour growth is assayed as described in example 15.

Definitions Antibody

This term describes an immunoglobulin whether natural or partly or wholly synthetically produced. The term also covers any polypeptide or protein comprising an antibody antigen-binding domain. Antibody fragments that comprise an antibody antigen-binding domain include whole antibodies (for example an IgG antibody comprising VH, CH1, CH2, CH3, VL, and CL domains in the canonical arrangement), or fragments of whole antibodies that retain their binding activity for a target antigen. Such fragments include Fv (fragment variable), Fab (fragment antibody binding) and F(ab′)₂ fragments, as well as single-chain Fv antibodies (scFv), dsFv, minibodies, diabodies, single-chain diabodies, tandem scFv, TandAb, bi-body, tri-body, kappa(lambda) body, BiTE, DVD-Ig, SIP, SMIP, or DART. Furthermore, the antibodies and fragments thereof may be humanised antibodies, for example as described in EP239400A. For example: monoclonal and polyclonal antibodies, recombinant antibodies, proteolytic and recombinant fragments of antibodies (Fab, Fv, scFv, diabodies), single-domain antibodies (VHH, sdAb, nanobodies, IgNAR, VNAR), and proteins unrelated to antibodies, that have been engineered to have antibody-like specific binding (antibody mimetics), such as the following, but not limited to:

Name Based on: Adnectins/ 10th type III domain of human fibronectin (10Fn3), Monobodies 10 kDa Affibodies Protein A, Z domain, 6 kDa) Affilins Human γ-crystallin/human ubiquitin (10-20 kDa) Affitins Sac7d (from Sulfolobus acidocaldarius), 7 kDa Anticalins Lipocalins, 20 kDa Avimers Domains of various membrane receptors, 9-18 kDa DARPins Ankyrin repeat motif, 14 kDa Evibody Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4), 15 kDa Fynomers Fyn, SH3 domain, 7 kDa Kunitz domain Various protease inhibitors, 6 kDa peptides

An antibody may comprise all or apportion of an antibody heavy chain constant region and/or an antibody light chain constant region.

It is possible to take monoclonal and other antibodies and use techniques of recombinant DNA technology to produce engineered antibodies or chimeric molecules, that retain the specificity of the original antibody. Such techniques may involve ligation of DNA fragments encoding the immunoglobulin variable regions, or the complementarity determining regions (CDRs), of an antibody with genes coding for the immunoglobulin constant regions, or the constant regions plus framework regions, of a different immunoglobulin. See, for instance, EPA-184187, GB 2188638A or EP-A-239400. A hybridoma or other cell producing an antibody may be subject to genetic mutation or other changes, that may or may not alter the binding specificity of antibodies produced.

As antibodies can be modified in a number of ways, the term “antibody molecule” should be construed as covering any polypeptide or other molecule having an antibody-derived antigen-binding domain with the required specificity. Thus, this term covers antibody fragments and derivatives, including any polypeptide comprising an immunoglobulin binding domain, whether natural or wholly or partially synthetic. Chimeric molecules comprising an immunoglobulin binding domain, or equivalent, fused to another polypeptide are therefore included. Cloning and expression of chimeric antibodies are described in EP-A-0120694 and EP-A0125023.

It has been shown that fragments of a whole antibody can perform the function of binding antigens. Examples of binding fragments are (i) the Fab fragment consisting of VL, VH, CL and CH1 domains; (ii) the Fd fragment consisting of the VH and CH1 domains; (iii) the Fv fragment consisting of the VL and VH domains of a single antibody; (iv) the dAb fragment (Ward, E. S. et al., Nature 341, 544-546 (1989)) that consists of a VH domain; (v) isolated CDR regions; (vi) F(ab′)2 fragments, a bivalent fragment comprising two linked Fab fragments; (vii) single chain Fv molecules (scFv), wherein a VH domain and a VL domain are linked by a peptide linker that allows the two domains to associate to form an antigen binding site (Bird et al, Science, 242, 423-426, 1988; Huston et al, PNAS USA, 85, 5879-5883, 1988); (viii) bispecific single chain Fv dimers (PCT/US92/09965) and (ix) “diabodies”, multivalent or multispecific fragments constructed by gene fusion (WO94/13804; P. Holliger et al, Proc. Natl. Acad. Sci. USA 90, 6444-6448, 1993). Fv, scFv or diabody molecules may be stabilised by the incorporation of disulphide bridges linking the VH and VL domains (Y. Reiter et al, Nature Biotech, 14, 1239-1245, 1996). Minibodies comprising a scFv joined to a CH3 domain may also be made (S. Hu et al, Cancer Res., 56, 3055-3061, 1996).

The antibody may be bispecific or multispecific. Where bispecific antibodies are to be used, these may be conventional bispecific antibodies, that can be manufactured in a variety of ways (Holliger, P. and Winter G. Current Opinion Biotechnol. 4, 446-449 (1993)), e.g. prepared chemically or from hybrid hybridomas, or may be any of the bispecific antibody fragments mentioned above. Diabodies and scFv can be constructed without an Fc region, using only variable domains, potentially reducing the side effects, such as those due to the antibody effector functions, or human-anti-mouse antibody (HAMA) response in case of using antibodies of murine origin.

Bispecific diabodies, as opposed to bispecific whole antibodies, may also be particularly useful because they can be readily constructed and expressed in bacteria (e.g. Escherichia coli). Diabodies (and many other polypeptides such as antibody fragments) of appropriate binding specificities can be readily selected using phage display (WO94/13804) from the antibody libraries. If one arm of the diabody is to be kept constant, for instance, with a specificity directed against Axl, then a library can be made where the other arm is varied and an antibody of appropriate specificity selected. Bispecific whole antibodies may be made by “knobs-intoholes” engineering (J. B. B. Ridgeway et al, Protein Eng., 9, 616-621, 1996).

Sample

As used herein, a “sample” may be a single cell or a population of cells. The cell(s) may be normal, healthy cell(s) or may be tumour cells, such as circulating tumour cells.

The sample may be in vivo, ex vivo, or in vitro. For example, the sample may be an in vivo tumour mass, or an in vitro cell population.

Antigen Binding Domain

This describes the part of an antibody molecule that comprises the area that recognizes and specifically binds to and is complementary part or all of an antigen. Where an antigen is large, an antibody may only bind to a particular part of the antigen, which part is termed an epitope. An antigen binding domain may be provided by one or more antibody variable domains (e.g. a so-called Fd antibody fragment consisting of a VH domain). Preferably, an antigen binding domain comprises an antibody light chain variable region (VL) and an antibody heavy chain variable region (VH).

Specific Proteins Human Axl

As used herein, ‘human Axl’ refers to the Axl member of the human TAM family of receptor tyrosine kinases. Human Axl occurs in the following isoforms:

Axl Isoform mRNA: NCBI reference Polypeptide: NCBI reference A NM_001278599.1, GI:520260398, record NP_001265528.1, GI:520260399, record update date: Nov. 28, 2014 12:30 AM update date: Nov. 28, 2014 12:30 AM (SEQ ID NO. 37) B NM_001699.5, GI: 520260376, record NP_001690.2, GI:21536468, record update date: Nov. 28, 2014 12:30 AM update date: Nov. 28, 2014 12:30 AM C NM_021913.4, GI:520260356, record NP_068713.2, GI:21536466, record update date: Nov. 28, 2014 12:30 AM update date: Nov. 28, 2014 12:30 AM

In some embodiments, the human Ax polypeptide corresponds to Isoform “A”, shown above. In some embodiments, the human Axl polypeptide corresponds to Isoform “B”, shown above. In some embodiments, the human Axl polypeptide corresponds to Isoform “C”, shown above.

Murine Axl

As used herein, ‘murine Axl’ refers to the Axl member of the murine TAM family of receptor tyrosine kinases. Murine Axl occurs in the following isoforms:

Axl Isoform mRNA: NCBI reference Polypeptide: NCBI reference A NM_001190974.1, GI:300794859, record NP_001177903.1, GI:300794860, record update date: Sep. 5, 2014 08:46 PM update date: Sep. 5, 2014 08:46 PM (SEQ ID NO. 38) B NM_001190975.1, GI:300794883, record NP_001177904.1, GI:300794884, record update date: Sep. 5, 2014 08:46 PM update date: Sep. 5, 2014 08:46 PM C NM_009465.4, GI:300794836, record NP_033491.2, GI:31542164, record update date: Sep. 5, 2014 08:46 PM update date: Sep. 5, 2014 08:46 PM

In some embodiments, the murine Axl polypeptide corresponds to Isoform “A”, shown above. In some embodiments, the murine Axl polypeptide corresponds to Isoform “B”, shown above. In some embodiments, the murine Axl polypeptide corresponds to Isoform “C”, shown above.

Human Tyro3

As used herein, ‘human Tyro3’ refers to the Tyro3 member of the human TAM family of receptor tyrosine kinases. In some embodiments, the human Tyro3 polypeptide corresponds to NCBI accession no. NP_006284.2, GI:27597078, record update date: Nov. 28, 2014 12:30 AM (SEQ ID NO.39). In one embodiment, the nucleic acid encoding the human Tyro3 polypeptide corresponds to NCBI accession no. NM_006293.3, GI:295842183, record update date: Nov. 28, 2014 12:30 AM.

Human Mer

As used herein, ‘human Mer’ refers to the Mer member of the human TAM family of receptor tyrosine kinases. In some embodiments, the human Mer polypeptide corresponds to NCBI accession no. NP_006334.2, GI:66932918, record update date: Sep. 6, 2014 04:03 AM (SEQ ID NO.40). In one embodiment, the nucleic acid encoding the human Mer polypeptide corresponds to NCBI accession no. NM_006343, version no. NM_006343.2 GI:66932917, record update date: Sep. 6, 2014 04:03 AM.

Human Akt3

As used herein, ‘human Akt3’ refers to the Akt3 member of the human AKT subfamily of serine/threonine protein kinases. Human Akt3 occurs in the following isoforms:

Akt 3 Isoform mRNA: NCBI reference Polypeptide: NCBI reference A NM_001206729.1, GI:332078558, record NP_001193658.1, GI:332078559, record update date: Sep. 6, 2014 02:43 AM update date: Sep. 6, 2014 02:43 AM (SEQ ID NO. 41) B NM_005465.4, GI:332078467, record NP_005456.1, GI: 4885549, record update date: Sep. 6, 2014 02:43 AM update date: Sep. 6, 2014 02:43 AM C NM_181690.2, GI:332078557, record NP_859029.1, GI: 32307163, record update date: Sep. 6, 2014 02:43 AM update date: Sep. 6, 2014 02:43 AM

In some embodiments, the human Akt polypeptide corresponds to Isoform “A”, shown above. In some embodiments, the human Akt polypeptide corresponds to Isoform “B”, shown above. In some embodiments, the human Akt polypeptide corresponds to Isoform “C”, shown above.

Human Gas6

As used herein, ‘human Gas6’ (Growth Arrest Specific 6) refers to a ligand of the TAM family of receptor tyrosine kinases. In some embodiments, the human Gas6 polypeptide corresponds to NCBI accession no. NP_000811.1, GI:4557617, record update date: Sep. 6, 2014 02:44 AM (SEQ ID NO.42). In one embodiment, the nucleic acid encoding the human Gas6 polypeptide corresponds to NCBI accession no. NM_000820.3, GI:673038877, record update date: Sep. 6, 2014 02:44 AM.

BSA

As used herein, ‘BSA’ refers to Bovine Serum Albumin. In some embodiments BSA corresponds to ‘A9647—Bovine Serum Albumin’ (Sigma Aldrich). In some embodiments BSA corresponds to Genbank accession no. CAA76847, version no. CAA76847.1 GI:3336842, record update date: Jan. 7, 2011 02:30 PM.

Comprise

This is generally used in the sense of “include”, that is to say permitting the presence of one or more features or components.

Isolated

This refers to the state in which antibodies of the invention, or nucleic acid encoding such antibody, will generally be in accordance with the present invention. Antibody and nucleic acid will be free or substantially free of material with which they are naturally associated such as other polypeptides or nucleic acids with which they are found in their natural environment, or the environment in which they are prepared (e.g. cell culture) when such preparation is by recombinant DNA technology practiced in vitro or in vivo. Antibodies and nucleic acid may be formulated with diluents or adjuvants and still for practical purposes be isolated—for example the antibody will normally be mixed with gelatin or other carriers if used to coat microtitre plates for use in immunoassays, or will be mixed with pharmaceutically acceptable carriers or diluents when used in diagnosis or therapy. Antibodies may be glycosylated, either naturally or by systems of heterologous eukaryotic cells (e.g. CHO or NS0 (ECACC 85110503) cells), or they may be (for example, if produced by expression in a prokaryotic cell) non-glycosylated.

Substantially as Set Out

By “substantially as set out” it is meant that the relevant CDR or VH or VL domain of the invention will be either identical or highly similar to the specified regions of which the sequence is set out herein. By “highly similar” it is contemplated that from 1 to 5, preferably from 1 to 4 such as 1 to 3 or 1 or 2, or 3 or 4, amino acid substitutions may be made in the CDR and/or VH or VL domain.

Frameworks Supporting CDRs

The structure for carrying a CDR of the invention will generally be of an antibody heavy or light chain sequence or substantial portion thereof in which the CDR is located at a location corresponding to the CDR of naturally occurring VH and VL antibody variable domains encoded by rearranged immunoglobulin genes. The structures and locations of immunoglobulin variable domains may be determined by reference to (Kabat, E. A. et al, Sequences of Proteins of Immunological Interest. 4th Edition. US Department of Health and Human Services. 1987, and updates thereof, now available on the Internet (immuno.bme.nwu.edu or find “Kabat” using any search engine).

Variable domains employed in the invention may be obtained from any germ-line or rearranged mouse or human variable domain, or may be a synthetic variable domain based on consensus sequences of known mouse or human variable domains. A CDR sequence of the invention (e.g. CDR3) may be introduced into a repertoire of variable domains lacking a CDR (e.g. CDR3), using recombinant DNA technology.

For example, Marks et al (Bio/Technology, 1992, 10:779-783) describe methods of producing repertoires of antibody variable domains in which consensus primers directed at or adjacent to the 5′-end of the variable domain area are used in conjunction with consensus primers to the third framework region of human VH genes to provide a repertoire of VH variable domains lacking a CDR3. Marks et al. further describe how this repertoire may be combined with a CDR3 of a particular antibody. Using analogous techniques, the CDR3-derived sequences of the present invention may be shuffled with repertoires of VH or VL domains lacking a CDR3, and the shuffled complete VH or VL domains combined with a cognate VL or VH domain to provide antibodies of the invention. The repertoire may then be displayed in a suitable host system such as the phage display system of WO92/01047 so that suitable antibodies may be selected. A repertoire may consist of from anything from 10⁴ individual antibody upwards, for example from 10⁶ to 10⁸ or 10¹⁰ antibodies.

Analogous shuffling or combinatorial techniques are also disclosed by Stemmer (Nature, 1994, 370:389-391), who describes the technique of DNA shuffling in relation to a β-lactamase gene but observes that the approach may be used for the generation of antibodies.

A further alternative is to generate novel VH or VL regions carrying a CDR-derived sequences of the invention using random mutagenesis of one or more selected VH and/or VL genes to generate mutations within the entire variable domain. Such a technique is described by Gram et al (1992, Proc. Natl. Acad. Sci., USA, 89:3576-3580), who used error-prone PCR.

Another method that may be used is to direct mutagenesis to CDR regions of VH or VL genes. Such techniques are disclosed by Barbas et al. (1994, Proc. Natl. Acad. Sci., USA, 91:3809-3813) and Schier et al. (1996, J. Mol. Biol. 263:551-567).

All the above-described techniques are known as such in the art and in themselves do not form part of the present invention. The skilled person will be able to use such techniques to provide antibodies of the invention using routine methodology in the art.

Epitope-Specific Antibodies

A further aspect of the invention provides a method for obtaining an antibody specific for an Axl epitope, the method comprising providing by way of addition, deletion, substitution or insertion of one or more amino acids in the amino acid sequence of a VH domain set out herein a VH domain that is an amino acid sequence variant of the VH domain, optionally combining the VH domain thus provided with one or more VL domains, and testing the VH domain or VH/VL combination or combinations to identify a antibody or an antibody antigen binding domain specific for Axl. Said VL domain may have an amino acid sequence which is substantially as set out herein.

To screen for antibodies that bind to the epitope on Axl bound by an antibody of interest (e.g., those that block binding of the 10C9 or 10G5 antibody to Axl), a routine cross-blocking assay such as that described in Antibodies. A Laboratory Manual. Cold Spring Harbor Laboratory. Ed Harlow and David Lane (1988), can be performed.

An analogous method may be employed in which one or more sequence variants of a VL domain disclosed herein are combined with one or more VH domains.

A further aspect of the invention provides a method of preparing an antibody specific for Axl, which method comprises:

-   -   (a) providing a starting repertoire of nucleic acids encoding a         VH domain that either includes a CDR3 to be replaced or lack a         CDR3 encoding region;     -   (b) combining said repertoire with a donor nucleic acid encoding         an amino acid sequence substantially as set out herein for a VH         CDR3 such that said donor nucleic acid is inserted into the CDR3         region in the repertoire, so as to provide a product repertoire         of nucleic acids encoding a VH domain;     -   (c) expressing the nucleic acids of said product repertoire;     -   (d) selecting an antibody specific for Axl; and     -   (e) recovering said antibody or nucleic acid encoding it.

Again, an analogous method may be employed in which a VL CDR3 of the invention is combined with a repertoire of nucleic acids encoding a VL domain that either includes a CDR3 to be replaced or lack a CDR3 encoding region.

Similarly, one or more, or all three CDRs may be grafted into a repertoire of VH or VL domains that are then screened for an antibody or antibodies specific for Axl.

A substantial portion of an immunoglobulin variable domain will comprise at least the three CDR regions, together with their intervening framework regions. Preferably, the portion will also include at least about 50% of either or both of the first and fourth framework regions, the 50% being the C-terminal 50% of the first framework region and the N-terminal 50% of the fourth framework region. Additional residues at the N-terminal or C-terminal end of the substantial part of the variable domain may be those not normally associated with naturally occurring variable domain regions. For example, construction of antibodies of the present invention made by recombinant DNA techniques may result in the introduction of N- or C-terminal residues encoded by linkers introduced to facilitate cloning or other manipulation steps. Other manipulation steps include the introduction of linkers to join variable domains of the invention to further protein sequences including immunoglobulin heavy chains, other variable domains (for example in the production of diabodies) or protein labels as discussed in more details below.

Although in a preferred aspect of the invention antibodies comprising a pair of VH and VL domains are preferred, single binding domains based on either VH or VL domain sequences form further aspects of the invention. It is known that single immunoglobulin domains, especially VH domains, are capable of binding target antigens in a specific manner.

In the case of either single binding domains, these domains may be used to screen for complementary domains capable of forming a two-domain antibody able to bind Axl.

This may be achieved by phage display screening methods using the so-called hierarchical dual combinatorial approach as disclosed in WO92/01047 in which an individual colony containing either an H or L chain clone is used to infect a complete library of clones encoding the other chain (L or H) and the resulting two-chain antibody is selected in accordance with phage display techniques such as those described in that reference. This technique is also disclosed in Marks et al., ibid.

Antibodies of the present invention may further comprise antibody constant regions or parts thereof. For example, an antibody of the present invention may comprise a CL, CH1, CH2, and/or a CH3 domain (or any combination thereof). A VL domain may be attached at its C-terminal end to antibody light chain constant domains including human Cκ or Cλ chains, preferably Cκ chains. Similarly, an antibody based on a VH domain may be attached at its C-terminal end to all or part of an immunoglobulin heavy chain derived from any antibody isotype, e.g. IgG, IgA, IgE and IgM and any of the isotype sub-classes. Fc regions such as Δnab and Δnac as disclosed in WO99/58572 may be employed.

Chimeric, Humanised and CDR-Grafted Antibodies

As used herein “chimeric” antibodies or “humanised” antibodies or “CDR-grafted” include any combination of the herein described anti-Axl antibodies, or any CDR derived therefrom combined with one or more proteins or peptides derived from a non-murine, preferably, human antibody.

Chimeric or humanised antibodies include those wherein the CDR's are derived from one or more of the herein described anti-Axl antibodies and at least a portion, or the remainder of the antibody is derived from one or more human antibodies. Thus, the human part of the antibody may include the frameworks, CL (e.g. Cκ or Cλ), CH domains (e.g., CH1, CH2, CH3), hinge regions that are substantially non-immunogenic in humans.

The regions of the antibody that are derived from human antibodies need not have 100% identity with human antibodies. In a preferred embodiment, as few of the mouse amino acid residues as possible are retained in order for the immunogenicity to be negligible, but the mouse residues may be retained as necessary to support the antigen binding site formed by the CDR's while simultaneously maximizing the humanization of the antibody. Such changes or variations optionally and preferably retain or reduce the immunogenicity in humans or other species relative to non-modified antibodies.

It should be noted that a humanised antibody can be produced by a non-human animal or prokaryotic or eukaryotic cell that is capable of expressing functionally rearranged human immunoglobulin (e.g., heavy chain and/or light chain) genes. Further, when the antibody is a single chain antibody, it can comprise a linker peptide that is not found in native human antibodies. For example, an scFv can comprise a linker peptide, such as two to about twenty glycine or other amino acid residues (preferably glycine and serine residues (e.g., Gly₄Ser or Gly₂Ser repeats)), that connects the variable region of the heavy chain and the variable region of the light chain. Such linker peptides are considered to be non-immunogenic in humans. In some embodiments the linker is of at least 12 amino acids in length.

Antibody humanisation can be performed by, for example, synthesizing a combinatorial library comprising all six CDRs of a non-human target monoclonal antibody fused in frame to a pool of individual human frameworks. A human framework library that contains genes representative of all known heavy and light chain human germline sequences can be utilized. The resulting combinatorial libraries can then be screened for binding to antigens of interest. This approach can allow for the selection of the most favourable combinations of fully human frameworks in terms of maintaining the binding activity to the parental antibody. Humanised antibodies can then be further optimized by a variety of techniques.

For full-length antibody molecules, the immunoglobulin genes can be obtained from genomic DNA or mRNA of hybridoma cell lines. The antibody heavy and light chains are cloned in a mammalian vector system. Assembly is confirmed by sequencing using methods known in the art. The antibody construct can be expressed in other human or mammalian host cell lines. The construct can then be validated by transient transfection assays and Western blot analysis of the expressed antibody of interest. Stable cell lines with the highest productivity can be isolated and screened using rapid assay methods.

Human genes that encode the constant (C) regions of the humanized antibodies, fragments and regions can be derived from a human fetal liver library by known methods. Human C region genes can be derived from any human cell including those that express and produce human immunoglobulins. The human CH region can be derived from any of the known classes or isotypes of human heavy chains, including γ, μ, α, δ, ε, and subclasses thereof, such as G1, G2, G3 and G4. Since the heavy chain isotype is responsible for the various effector functions of an antibody, the choice of CH domain will be guided by the desired effector functions, such as complement fixation, or activity in antibody-dependent cellular cytotoxicity (ADCC). Preferably, the CH domain are derived from the gamma 1 (IgG1).

The human CL region can be derived from either human L chain isotype, kappa or lambda, preferably kappa.

Genes encoding human immunoglobulin C regions are obtained from human cells by standard cloning techniques (Sambrook, et al. Molecular Cloning: A Laboratory Manual, 2nd Edition, Cold Spring Harbor Press, Cold Spring Harbor, N.Y. (1989) and Ausubel et al., eds. Current Protocols in Molecular Biology (1987-1993)). Human C region genes are readily available from known clones containing genes representing the two types of light chains, the five classes of heavy chains and subclasses thereof.

Chimeric antibody fragments, such as Fab and F(ab′)₂, can be prepared by designing a chimeric heavy chain gene that is appropriately truncated. For example, a chimeric gene encoding a heavy chain portion of an F(ab′)₂ fragment would include DNA sequences encoding the CH1 domain and hinge region of the heavy chain, followed by a translational stop codon to yield the truncated molecule.

Methods for engineering or humanizing non-human or human antibodies can be used and are well known in the art. Generally, a humanized or engineered antibody has one or more amino acid residues from a source that is non-human, e.g., but not limited to mouse, rat, rabbit, non-human primate or other mammal. These human amino acid residues are often referred to as “import” residues, which are typically taken from an “import” variable, constant or other domain of a known human sequence. Known human Ig sequences are disclosed, e.g., www.ncbi.nlm.nih.gov/entrez/query.fcgi; www.atcc.org/phage/hdb.html; www.sciquest.com/; www.abcam.com/; www.antibodyresource.com/onlinecomp.html; www.public.iastate.edu/.about.pedro/research_tools.html; www.mgen.uniheidelberg.de/SD/IT/IT.html; www.whfreeman.com/immunology/CHO5/kuby05.htm; www.library.thinkquest.org/12429/Immune/Antibody.html; www.hhmi.org/grants/lectures/1996/vlab/; www.path.cam.ac.uk/.about.mrc7/mikeimages.html; www.antibodyresource.com/; mcb.harvard.edu/BioLinks/Immunology.html. www.immunologylink.com/; pathbox.wustl.edu/.about.hcenter/index.html; www.biotech.ufl.edu/.about.hcl/; www.pebio.com/pa/340913/340913.html; www.nal.usda.gov/awic/pubs/antibody/; www.m.ehime-u.ac.jp/.about.yasuhito/Elisa.html; www.biodesign.com/table.asp; www.icnet.uk/axp/facs/davies/links.html; www.biotech.ufl.edu/.about.fccl/protocol.html; www.isac-net.org/sites_geo.html; aximt1.imt.unimarburg.de/.about.rek/AEPStart.html; baserv.uci.kun.nl/.about.jraats/links1.html; www.recab.uni-hd.de/immuno.bme.nwvu.edu/; www.mrc-cpe.cam.ac.uk/imtdoc/public/INTRO.html; www.ibt.unam.mx/vir/V_mice.html; imgt.cnusc.fr:8104/; www.biochem.ucl.ac.uk/.about.martin/abs/index.html; antibody.bath.ac.uk/; abgen.cvm.tamu.edu/lab/wwwabgen.html; www.unizh.ch/.about.honegger/AHOseminar/Slide01.html; www.cryst.bbk.ac.uk/.about.ubcg07s/; www.nimr.mrc.ac.uk/CC/ccaewg/ccaewg.htm; www.path.cam.ac.uk/.about.mrc7/humanisation/TAHHP.html; www.ibt.unam.mx/vir/structure/stat_aim.html; www.biosci.missouri.edu/smithgp/index.html; www.cryst.bioc.cam.ac.uk/.about.fmolina/Web-pages/Pept/spottech.html; www.jerini.de/fr_products.htm; www.patents.ibm.con/ibm.html. Kabat et al. Sequences of Proteins of Immunological Interest, U.S. Dept. Health (1983), each entirely incorporated herein by reference.

Such imported sequences can be used to reduce immunogenicity or reduce, enhance or modify binding, affinity, on-rate, off-rate, avidity, specificity, half-life, or any other suitable characteristic, as known in the art. Generally, part or all of the non-human or human CDR sequences are maintained while the non-human sequences of the variable and constant regions are replaced with human or other amino acids.

Antibodies can also optionally be humanized with retention of high affinity for the antigen and other favorable biological properties. To achieve this goal, humanized antibodies can be optionally prepared by a process of analysis of the parental sequences and various conceptual humanized products using three-dimensional models of the parental and humanized sequences. Three-dimensional immunoglobulin models are commonly available and are familiar to those skilled in the art. Computer programs are available which illustrate and display probable three-dimensional conformational structures of selected candidate immunoglobulin sequences. Inspection of these displays permits analysis of the likely role of the residues in the functioning of the candidate immunoglobulin sequence, i.e., the analysis of residues that influence the ability of the candidate immunoglobulin to bind its antigen. In this way, FR residues can be selected and combined from the consensus and import sequences so that the desired antibody characteristic, such as increased affinity for the target antigen(s), is achieved.

In general, the CDR residues are directly and most substantially involved in influencing antigen binding. Humanization or engineering the antibody can be performed using any known method, such as but not limited to those described in Winter et al., Nature 321:522 (1986); Riechmann et al., Nature 332:323 (1988); Verhoeyen et al., Science 239:1534 (1988)), Sims et al., J. Immunol. 151: 2296 (1993); Chothia and Lesk, J. Mol. Biol. 196:901 (1987), Carter et al., Proc. Natl. Acad. Sci. U.S.A. 89:4285 (1992); Presta et al., J. Immunol. 151:2623 (1993), U.S. Pat. Nos. 5,723,323, 5,976,862, 5,824,514, 5,817,483, 5,814,476, 5,763,192, 5,723,323, 5,766,886, 5,714,352, 6,204,023, 6,180,370, 5,693,762, 5,530,101, 5,585,089, 5,225,539; 4,816,567, PCT/: US98/16280, US96/18978, US91/09630, US91/05939, US94/01234, GB89/01334, GB91/01134, GB92/01755; WO90/14443, WO90/14424, WO90/14430, EP 229246.

The human constant region of the humanized antibody can be of any class or isotype (IgG, IgA, IgM, IgE, IgD, etc.) and can comprise a kappa or lambda light chain. In one embodiment, the human constant region comprises an IgG heavy chain or defined fragment, for example, at least one of the IgG subclasses, IgG1, IgG2, IgG3 or IgG4.

Labelled Antibodies

Antibodies of the invention may be labelled with a detectable or functional label. Detectable labels include radiolabels such as [¹³¹1] or [⁹⁹Tc], which may be attached to antibodies of the invention using conventional chemistry known in the art of radioimmunoconjugates. Labels also include enzyme labels such as horseradish peroxidase. Labels further include chemical moieties, such as biotin, which may be detected via binding to a specific cognate detectable moiety, e.g. labelled avidin or streptavidin. Preferably, the labels include fluorescent labels such as FITC.

Organic Moiety

The modified antibodies and antigen-binding fragments can comprise one or more organic moieties that are covalently bonded, directly or indirectly, to the antibody. Each organic moiety that is bonded to an antibody or antigen-binding fragment described herein can independently be a hydrophilic polymeric group, a fatty acid group or a fatty acid ester group. As used herein, the term “fatty acid” encompasses mono-carboxylic acids and di-carboxylic acids. A “hydrophilic polymeric group,” as the term is used herein, refers to an organic polymer that is more soluble in water than in octane. For example, poly-lysine is more soluble in water than in octane. Thus, an antibody modified by the covalent attachment of poly-lysine is encompassed by the present disclosure. Hydrophilic polymers suitable for modifying antibodies described herein can be linear or branched and include, for example, poly-alkane glycols, e.g., polyethylene glycol (PEG), monomethoxy-polyethylene glycol (mPEG), PPG and the like, carbohydrates (e.g., dextran, cellulose, oligosaccharides, polysaccharides and the like), polymers of hydrophilic amino acids (e.g., poly-lysine, poly-arginine, poly-aspartate and the like), poly-alkane oxides (e.g., polyethylene oxide, polypropylene oxide and the like) and polyvinyl pyrolidone. Preferably, the hydrophilic polymer that modifies the antibody described herein has a molecular weight of about 800 to about 150,000 Daltons as a separate molecular entity. For example PEG5000 and PEG20,000, wherein the subscript is the average molecular weight of the polymer in Daltons, can be used. The hydrophilic polymeric group can be substituted with one to about six alkyl, fatty acid or fatty acid ester groups. Hydrophilic polymers that are substituted with a fatty acid or fatty acid ester group can be prepared by employing suitable methods. For example, a polymer comprising an amine group can be coupled to a carboxylate of the fatty acid or fatty acid ester, and an activated carboxylate (e.g., activated with N,N-carbonyl diimidazole) on a fatty acid or fatty acid ester can be coupled to a hydroxyl group on a polymer.

Fatty acids and fatty acid esters suitable for modifying antibodies described herein can be saturated or can contain one or more units of unsaturation. Fatty acids that are suitable for modifying antibodies described herein include, for example, n-dodecanoate (C12, laurate), n-tetradecanoate (C14, myristate), n-octadecanoate (C18, stearate), n-eicosanoate (C20, arachidate), n-docosanoate (C22, behenate), n-triacontanoate (C30), n-tetracontanoate (C40), cis-δ 9-octadecanoate (C18, oleate), all cis-δ 5,8,11,14-eicosatetraenoate (C20, arachidonate), octanedioic acid, tetradecanedioic acid, octadecanedioic acid, docosanedioic acid, and the like. Suitable fatty acid esters include mono-esters of dicarboxylic acids that comprise a linear or branched lower alkyl group. The lower alkyl group can comprise from one to about twelve, preferably one to about six, carbon atoms.

The modified human antibodies and antigen-binding fragments can be prepared using suitable methods, such as by reaction with one or more modifying agents. A “modifying agent” as the term is used herein, refers to a suitable organic group (e.g., hydrophilic polymer, a fatty acid, a fatty acid ester) that comprises an activating group. An “activating group” is a chemical moiety or functional group that can, under appropriate conditions, react with a second chemical group thereby forming a covalent bond between the modifying agent and the second chemical group. For example, amine-reactive activating groups include electrophilic groups such as tosylate, mesylate, halo (chloro, bromo, fluoro, iodo), N-hydroxysuccinimidyl esters (NHS), and the like. Activating groups that can react with thiols include, for example, maleimide, iodoacetyl, acrylolyl, pyridyl disulfides, 5-thiol-2-nitrobenzoic acid thiol (TNB-thiol), and the like. An aldehyde functional group can be coupled to amine- or hydrazide-containing molecules, and an azide group can react with a trivalent phosphorous group to form phosphoramidate or phosphorimide linkages. Suitable methods to introduce activating groups into molecules are known in the art (see for example, Hernanson, G. T., Bioconjugate Techniques, Academic Press: San Diego, Calif. (1996)). An activating group can be bonded directly to the organic group (e.g., hydrophilic polymer, fatty acid, fatty acid ester), or through a linker moiety, for example a divalent C1-C12 group wherein one or more carbon atoms can be replaced by a heteroatom such as oxygen, nitrogen or sulfur. Suitable linker moieties include, for example, tetra-ethylene glycol, —(CH₂)₃—, —NH—(CH₂)₆—NH—, —(CH₂)₂—NH—and —CH₂—O—CH₂—CH₂—O—CH₂—CH₂—O—CH—NH—. Modifying agents that comprise a linker moiety can be produced, for example, by reacting a mono-Boc-alkyldiamine (e.g., mono-Boc-ethylenediamine, mono-Boc-diaminohexane) with a fatty acid in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) to form an amide bond between the free amine and the fatty acid carboxylate. The Boc protecting group can be removed from the product by treatment with trifluoroacetic acid (TFA) to expose a primary amine that can be coupled to another carboxylate as described, or can be reacted with maleic anhydride and the resulting product cyclized to produce an activated maleimido derivative of the fatty acid. (See, for example, Thompson, et al., WO 92/16221).

The modified antibodies can be produced by reacting a human antibody or antigen-binding fragment with a modifying agent. For example, the organic moieties can be bonded to the antibody in a non-site specific manner by employing an amine-reactive modifying agent, for example, an NHS ester of PEG. Modified human antibodies or antigen-binding fragments can also be prepared by reducing disulfide bonds (e.g., intra-chain disulfide bonds) of an antibody or antigen-binding fragment. The reduced antibody or antigen-binding fragment can then be reacted with a thiol-reactive modifying agent to produce the modified antibody described herein. Modified human antibodies and antigen-binding fragments comprising an organic moiety that is bonded to specific sites of an antibody described herein can be prepared using suitable methods, such as reverse proteolysis (Fisch et al., Bioconjugate Chem., 3:147-153 (1992); Werlen et al., Bioconjugate Chem., 5:411-417 (1994); Kumaran et al., Protein Sci. 6(10):2233-2241 (1997); Itoh et al., Bioorg. Chem., 24(1): 59-68 (1996); Capellas et al., Biotechnol. Bioeng., 56(4):456-463 (1997)), and the methods described in Hermanson, G. T., Bioconjugate Techniques, Academic Press: San Diego, Calif. (1996).

Immunoconjugates

The invention also provides immunoconjugates comprising an anti-Axl antibody herein conjugated to one or more cytotoxic agents, such as chemotherapeutic agents or drugs, growth inhibitory agents, toxins (e.g., protein toxins, enzymatically active toxins of bacterial, fungal, plant, or animal origin, or fragments thereof), or radioactive isotopes.

In one embodiment, an immunoconjugate is an antibody-drug conjugate (ADC) in which an antibody is conjugated to one or more drugs, including but not limited to a maytansinoid (see U.S. Pat. Nos. 5,208,020, 5,416,064 and European Patent EP 0 425 235 B1); an auristatin such as monomethylauristatin drug moieties DE and DF (MMAE and MMAF) (see U.S. Pat. Nos. 5,635,483 and 5,780,588, and 7,498,298); a dolastatin; a calicheamicin or derivative thereof (see U.S. Pat. Nos. 5,712,374, 5,714,586, 5,739,116, 5,767,285, 5,770,701, 5,770,710, 5,773,001, and 5,877,296; Hinman et al., Cancer Res. 53:3336-3342 (1993); and Lode et al., Cancer Res. 58:2925-2928 (1998)); an anthracycline such as daunomycin or doxorubicin (see Kratz et al., Current Med. Chern. 13:477-523 (2006); Jeffrey et al., Bioorganic & Med. Chern. Letters 16:358-362 (2006); Torgov et al., Bioconj. Chern. 16:717-721 (2005); Nagy et al., Proc. Natl. Acad. Sci. USA 97:829-834 (2000); Dubowchik et al., Bioorg. & Med. Chern. Letters 12:1529-1532 (2002); King et al., J. Med. Chern. 45:4336-4343 (2002); and U.S. Pat. No. 6,630,579); methotrexate; vindesine; a taxane such as docetaxel, paclitaxel, larotaxel, tesetaxel, and ortataxel; a trichothecene; and CC1065.

In another embodiment, an immunoconjugate comprises an antibody as described herein conjugated to an enzymatically active toxin or fragment thereof, including but not limited to diphtheria toxin A chain, nonbinding active fragments of diphtheria toxin, exotoxin A chain (from Pseudomonas aeruginosa), ricin A chain, abrin A chain, modeccin A chain, alpha-sarcin, Aleurites fordii proteins, dianthin proteins, Phytolaca americana proteins (P API, P APII, and PAP-S), Momordica charantia inhibitor, curcin, crotin, Sapaonaria officinalis inhibitor, gelonin, mitogellin, restrictocin, phenomycin, enomycin, and the tricothecenes.

In another embodiment, an immunoconjugate comprises an antibody as described herein conjugated to a radioactive atom to form a radioimmunoconjugate. A variety of radioactive isotopes are available for the production of radioimmunoconjugates. Examples include [²¹¹At], [¹³¹I], [¹²⁵I], [⁹⁰Y], [¹⁸⁶Re], [¹⁸⁸Re], [¹⁵³Sm], [²¹²Bi], [³²P], [²¹²Pb] and radioactive isotopes of Lu. When the radioimmunoconjugate is used for detection, it may comprise a radioactive atom for scintigraphic studies, for example [⁹⁹Tc] or [¹²³I], or a spin label for nuclear magnetic resonance (NMR) imaging (also known as magnetic resonance imaging, MRI), such as iodine-123 again, iodine-131, indium-111, fluorine-19, carbon-13, nitrogen-15, oxygen-17, gadolinium, manganese or iron.

Conjugates of an antibody and cytotoxic agent may be made using a variety of bifunctional protein coupling agents such as N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP), succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC), iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate HCl), active esters (such as disuccinimidyl suberate), aldehydes (such as glutaraldehyde), bis-azido compounds (such as bis (p-azidobenzoyl) hexanediamine), bis-diazonium derivatives (such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such as toluene 2,6-diisocyanate), and bis-active fluorine compounds (such as 1,5-difluoro-2,4-dinitrobenzene). For example, a ricin immunotoxin can be prepared as described in Vitetta et al., Science 238:1098 (1987). Carbon-14-labeled 1-isothiocyanatobenzyl-3-methyldiethylene triaminepentaacetic acid (MXDTPA) is an exemplary chelating agent for conjugation of radionucleotide to the antibody. See WO94/11026. The linker may be a “cleavable linker” facilitating release of a cytotoxic drug in the cell. For example, an acid-labile linker, peptidase-sensitive linker, photo-labile linker, dimethyl linker or disulfide-containing linker (Chari et al., Cancer Res. 52: 127-131 (1992); U.S. Pat. No. 5,208,020) may be used.

The immunoconjugates or ADCs herein expressly contemplate, but are not limited to such conjugates prepared with cross-linker reagents including, but not limited to, BMPS, EMCS, GMBS, HBVS, LC-SMCC, MBS, MPBH, SBAP, SIA, SIAB, SMCC, SMPB, SMPH, sulfo-EMCS, sulfo-GMBS, sulfo-KMUS, sulfo-MBS, sulfo-SIAB, sulfo-SMCC, and sulfo-SMPB, and SVSB (succinimidyl-(4-vinylsulfone)benzoate) which are commercially available (e.g., from Pierce Biotechnology, Inc., Rockford, IL., U.S.A).

Glycosylation Variants

In certain embodiments, an antibody provided herein is altered to increase or decrease the extent to which the antibody is glycosylated. Addition or deletion of glycosylation sites to an antibody may be conveniently accomplished by altering the amino acid sequence such that one or more glycosylation sites is created or removed.

Where the antibody comprises an Fc region, the carbohydrate attached thereto may be altered. Native antibodies produced by mammalian cells typically comprise a branched, biantennary oligosaccharide that is generally attached by an N-linkage to Asn297 of the CH2 domain of the Fc region. See, e.g., Wright et al. TIBTECH 15:26-32 (1997). The oligosaccharide may include various carbohydrates, e.g., mannose, N-acetyl glucosamine (GlcNAc), galactose, and sialic acid, as well as a fucose attached to a GlcNAc in the “stem” of the biantennary oligosaccharide structure. In some embodiments, modifications of the oligosaccharide in an antibody of the invention may be made in order to create antibody variants with certain improved properties.

In one embodiment, antibody variants are provided having a carbohydrate structure that lacks fucose attached (directly or indirectly) to an Fc region. For example, the amount of fucose in such antibody may be from 1% to 80%, from 1% to 65%, from 5% to 65% or from 20% to 40%. The amount of fucose is determined by calculating the average amount of fucose within the sugar chain at Asn297, relative to the sum of all glycostructures attached to Asn297 (e. g., complex, hybrid and high mannose structures) as measured by MALDI-TOF mass spectrometry, as described in WO 2008/077546, for example. Asn297 refers to the asparagine residue located at about position 297 in the Fc region (Eu numbering of Fc region residues); however, Asn297 may also be located about ±3 amino acids upstream or downstream of position 297, i.e., between positions 294 and 300, due to minor sequence variations in antibodies. Such fucosylation variants may have improved ADCC function. See, e.g., US Patent Publication Nos. US 2003/0157108 (Presta, L.); US 2004/0093621 (Kyowa Haklw Kogyo Co., Ltd). Examples of publications related to “defucosylated” or “fucose-deficient” antibody variants include: US2003/01571; WO2000/61739; WO2001/29246; US2003/0115614; US2002/0164328; US2004/0093621; US2004/0132140; US2004/0110704; US2004/0110282; US2004/0109865; WO2003/085119; WO2003/084570; WO2005/035586; WO2005/035778; WO2005/053742; WO2002/031140; Okazaki et al. J. Mol. Biol. 336:1239-1249 (2004); Yamane-Ohnuki et al. Biotech. Bioeng. 87: 614 (2004).

Examples of cell lines capable of producing defucosylated antibodies include Lecl3 CHO cells deficient in protein fucosylation (Ripka et al. Arch. Biochem. Biophys. 249:533-545 (1986); US Pat Appl No US 2003/0157108 A1, Presta, L; and WO 2004/056312 A1, Adams et al., especially at Example 11), and knockout cell lines, such as alpha-1,6-fucosyltransferase gene, FUT8, knockout CHO cells (see, e.g., Yamane-Ohnuki et al. Biotech. Bioeng. 87: 614 (2004); Kanda, Y. et al., Biotechnol. Bioeng., 94(4):680-688 (2006); and WO2003/085107).

Antibodies variants are further provided with bisected oligosaccharides, e.g., in which a biantennary oligosaccharide attached to the Fc region of the antibody is bisected by GlcNAc. Such antibody variants may have reduced fucosylation and/or improved ADCC function. Examples of such antibody variants are described, e.g., in WO 2003/011878 (Jean-Mairet et al.); U.S. Pat. No. 6,602,684 (Umana et al.); and US2005/0123546 (Umana et al.). Antibody variants with at least one galactose residue in the oligosaccharide attached to the Fe region are also provided. Such antibody variants may have improved CDC function. Such antibody variants are described, e.g., in WO 1997/30087 (Patel et al.); WO 1998/58964 (Raju, S.); and WO 1999/22764 (Raju, S.).

Fc Region Variants

In certain embodiments, one or more amino acid modifications may be introduced into the Fc region of an antibody provided herein, thereby generating an Fc region variant. The Fc region variant may comprise a human Fc region sequence (e.g., a human IgG1, IgG2, IgG3 or IgG4 Fc region) comprising an amino acid modification (e.g. a substitution) at one or more amino acid positions.

In certain embodiments, the invention contemplates an antibody variant that possesses some but not all effector functions, which make it a desirable candidate for applications in which the half-life of the antibody in vivo is important yet certain effector functions (such as complement fixation and ADCC) are unnecessary or deleterious. In vitro and/or in vivo cytotoxicity assays can be conducted to confirm the reduction/depletion of CDC and/or ADCC activities. For example, Fc receptor (FcR) binding assays can be conducted to ensure that the antibody lacks Fcγ binding (hence likely lacking ADCC activity), but retains FcRn binding ability. The primary cells for mediating ADCC, NK cells, express FcγRIII only, whereas monocytes express FcγRI, FcγRII and FcγRIII. FcR expression on hematopoietic cells is summarized in Table 3 on page 464 of Ravetch and Kinet, Annu. Rev. Immunol. 9:457-492 (1991). Nonlimiting examples of in vitro assays to assess ADCC activity of a molecule of interest is described in U.S. Pat. No. 5,500,362 (see, e.g. Hellstrom, I. et al. Proc. Nat'l Acad. Sci. USA 83:7059-7063 (1986)) and Hellstrom, I et al., Proc. Nat'l Acad. Sci. USA 82:1499-1502 (1985); 5,821,337 (see Bruggemann, M. et al., J. Exp. Med. 166:1351-1361 (1987)). Alternatively, nonradioactive assay methods may be employed (see, for example, ACTI™ non-radioactive cytotoxicity assay for flow cytometry (CellTechnology, Inc. Mountain View, CA; and CytoTox 96@non-radioactive cytotoxicity assay (Promega, Madison, WI). Useful effector cells for such assays include peripheral blood mononuclear cells (PBMC) and Natural Killer (NK) cells. Alternatively, or additionally, ADCC activity of the molecule of interest may be assessed in vivo, e.g., in an animal model such as that disclosed in Clynes et al. Proc. Nat'l Acad. Sci. USA 95:652-656 (1998). C1q binding assays may also be carried out to confirm that the antibody is unable to bind C1q and hence lacks complement-dependent cytotoxicity (CDC) activity. See, e.g., C1q and C3c binding ELISA in WO2006/029879 and WO2005/100402. To assess complement activation, a CDC assay may be performed (see, for example, Gazzano-Santoro et al., J. Immunol. Methods 202:163 (1996); Cragg, M. S. et al., Blood 101:1045-1052 (2003); and Cragg, M. S. and M. J. Glennie, Blood 103:2738-2743 (2004)). FcRn binding and in vivo clearance/half-life Fc determinations can also be performed using methods known in the art (see, e.g., Petkova, S. B. et al., Int'l. Immunol. 18(12): 1759-1769 (2006)).

Antibodies with reduced effector function include those with substitution of one or more of Fc region residues 238, 265, 269, 270, 297, 327 and 329 (U.S. Pat. No. 6,737,056). Such Fc mutants include Fc mutants with substitutions at two or more of amino acid positions 265, 269, 270, 297 and 327, including the so-called “DANA” Fc mutant with substitution of residues 265 and 297 to alanine (U.S. Pat. No. 7,332,581).

Certain antibody variants with improved or diminished binding to FcRs are described (see, e.g., U.S. Pat. No. 6,737,056; WO 2004/056312, and Shields et al., J. Biol. Chem. 9(2): 6591-6604 (2001)).

In certain embodiments, an antibody variant comprises an Fc region with one or more amino acid substitutions, that improve ADCC activity, e.g., substitutions at positions 298, 333, and/or of the Fc region (EU numbering of residues).

In some embodiments, alterations are made in the Fc region that result in altered (i.e., either improved or diminished) C1q binding and/or CDC activity, e.g., as described in U.S. Pat. No. 6,194,551, WO 99/51642, and Idusogie et al. J. Immunol. 164: 4178-4184 (2000).

Antibodies with increased half-lives and improved binding to the neonatal Fc receptor (FcRn), that is responsible for the transfer of maternal IgGs to the fetus (Guyer et al., J. Immunol. 117:587 (1976) and Kim et al., J. Immunol. 24:249 (1994)), are described in US2005/0014934A1 (Hinton et al.). Those antibodies comprise an Fc region with one or more substitutions therein that improve binding of the Fc region to FcRn. Such Fc variants include those with substitutions at one or more of Fc region residues: 238, 256, 265, 272, 286, 303, 305, 307, 311, 312, 317, 340, 356, 360, 362, 376, 378, 380, 382, 413, 424 or 434, e.g., substitution of Fc region residue 434 (U.S. Pat. No. 7,371,826). See also Duncan & Winter, Nature 322:738-40 (1988); U.S. Pat. Nos. 5,648,260; 5,624,821; and WO 94/29351 concerning other examples of Fc region variants.

Cysteine Engineered Antibody Variants

In certain embodiments, it may be desirable to create cysteine engineered antibodies, e.g., “thioMAbs,” in which one or more residues of an antibody are substituted with cysteine residues.

In particular embodiments, the substituted residues occur at accessible sites of the antibody. By substituting those residues with cysteine, reactive thiol groups are thereby positioned at accessible sites of the antibody and may be used to conjugate the antibody to other moieties, such as drug moieties or linker-drug moieties, to create an immunoconjugate, as described further herein. In certain embodiments, any one or more of the following residues may be substituted with cysteine: V205 (Kabat numbering) of the light chain; A118 (EU numbering) of the heavy chain; and S400 (EU numbering) of the heavy chain Fc region. Cysteine engineered antibodies may be generated as described, e.g., in U.S. Pat. No. 7,521,541.

Methods of Diagnosis and Treatment

Antibodies of the present invention are designed to be used in methods of diagnosis or treatment in human or animal subjects, preferably human.

Accordingly, further aspects of the invention provide methods of diagnosis comprising administration of an antibody as provided, with one or more reagents e.g. conjugated to a detectable label such as FITC. The antibody as provided may be used in the development of a rapid and reliable test for cancer cells derived from biopsied tissue. For example, the antibody may be used as a test for metastatic cancer cells, such as circulating tumour cells, that may be found circulating in body fluids such as blood or lymph. Other cancers of interest include breast, lung, gastric, head and neck, colorectal, renal, pancreatic, uterine, hepatic, bladder, endometrial and prostate cancers as well as lymphomas (e.g., non-Hodgkin's lymphoma, NHL) and leukemia (particularly acute myeloid leukemia, AML).

Further aspects of the invention provide methods of treatment comprising administration of an antibody as provided, pharmaceutical compositions comprising such an antibody, the antibody as described herein for use in a method of treatment, the antibody as described herein for use in a method of treatment of particular clinical indications described herein, and use of such an antibody in the manufacture of a medicament for administration, for example in a method of making a medicament or pharmaceutical composition comprising formulating the antibody with a pharmaceutically acceptable excipient.

Clinical Indications

Clinical indications in which an antibody with high specificity for human Axl may be used to provide therapeutic benefit include any condition in which Axl is overexpressed, or wherein Axl antagonism will provide a clinical benefit. These include immune disorders, cardiovascular disorders, thrombosis, diabetes, immune checkpoint disorders, fibrotic disorders (fibrosis), or proliferative diseases such as cancer, particularly metastatic cancer. Furthermore, Axl is known to play a role in many cancers of epithelial origin.

Fibrotic disorders of interest include strabmisus, scleroderma, keloid, Nephrogenic systemic fibrosis, pulmonary fibrosis, idiopathic pulmonary fibrosis (IPF), cystic fibrosis (CF), systemic sclerosis, cardiac fibrosis, non-alcoholic steatohepatitis (NASH), other types of liver fibrosis, primary biliary cirrhosis, renal fibrosis, cancer, and atherosclerosis. In these diseases, the chronic development of fibrosis in tissue leads to marked alterations in the architecture of the affected organs and subsequently cause defective organ function. As a result of this process of sustained attrition to organs, many diseases that involve fibrosis are often progressive conditions and have a poor long-term prognosis (see Rockey, D. C., Bell, P. D. and Hill, J. A. (2015), N. Engl. Med., Vol. 372, pp. 1138-1149).

Immune checkpoint disorders of interest include: Chronic viral infections, Melanoma, Colorectal cancer, Breast cancer, Ovarian cancer, Non-small cell lung cancer (NSCLC), Prostate cancer, Renal cell cancer, Pancreatic cancer, Esophagus cancer, Bladder cancer, Myeloma, Kidney cancer, Bladder cancer, Brain tumor, and Lymphoma.

Cancers of interest include: leukaemias such as but not limited to, acute leukemia, acute lymphocytic leukemia, acute myelocytic leukaemias such as myeloblastic, promyelocytic, myelomonocytic, monocytic, erythroleukaemia leukaemias and myelodysplastic syndrome, chronic leukaemias such as but not limited to, chronic myelocytic (granulocytic) leukemia, chronic lymphocytic leukemia, hairy cell leukemia; polycythemia vera; lymphomas such as but not limited to Hodgkin's disease, non-Hodgkin's disease; multiple myelomas such as but not limited to smoldering multiple myeloma, nonsecretory myeloma, osteosclerotic myeloma, plasma cell leukemia, solitary plasmacytoma and extramedullary plasmacytoma; Waldenstrom's macroglobulinemia; monoclonal gammopathy of undetermined significance; benign monoclonal gammopathy; heavy chain disease; bone and connective tissue sarcomas such as but not limited to bone sarcoma, osteosarcoma, chondrosarcoma, Ewing's sarcoma, malignant giant cell tumor, fibrosarcoma of bone, chordoma, periosteal sarcoma, soft-tissue sarcomas, angiosarcoma (hemangiosarcoma), fibrosarcoma, Kaposi's sarcoma, leiomyosarcoma, liposarcoma, lymphangiosarcoma, metastatic cancers, neurilemmoma, rhabdomyosarcoma, synovial sarcoma; brain tumors such as but not limited to, glioma, glioblastoma, astrocytoma, brain stem glioma, ependymoma, oligodendroglioma, nonglial tumor, acoustic neurinoma, craniopharyngioma, medulloblastoma, meningioma, pineocytoma, pineoblastoma, primary brain lymphoma; breast cancer, including, but not limited to, adenocarcinoma, lobular (small cell) carcinoma, intraductal carcinoma, medullary breast cancer, mucinous breast cancer, tubular breast cancer, papillary breast cancer, primary cancers, Paget's disease, and inflammatory breast cancer; adrenal cancer such as but not limited to pheochromocytoma, and adrenocortical carcinoma; thyroid cancer such as but not limited to papillary or follicular thyroid cancer, Medullary thyroid carcinoma, medullary thyroid cancer and anaplastic thyroid cancer; GIST—gastrointestinal stromal tumor; pancreatic cancer such as but not limited to, insulinoma, gastrinoma, glucagonoma, vipoma, somatostatin-secreting tumor, and carcinoid or islet cell tumor; pituitary cancers such as but limited to Cushing's disease, prolactin-secreting tumor, acromegaly, and diabetes insipius; eye cancers such as but not limited to ocular melanoma such as iris melanoma, choroidal melanoma, and cilliary body melanoma, and retinoblastoma; vaginal cancers such as squamous cell carcinoma, adenocarcinoma, and melanoma; vulvar cancer such as squamous cell carcinoma, melanoma, adenocarcinoma, basal cell carcinoma, sarcoma, and Paget's disease; cervical cancers such as but not limited to, squamous cell carcinoma, and adenocarcinoma; uterine cancers such as but not limited to endometrial carcinoma and uterine sarcoma; ovarian cancers such as but not limited to, ovarian epithelial carcinoma, borderline tumor, germ cell tumor, and stromal tumor; esophageal cancers such as but not limited to, squamous cancer, adenocarcinoma, adenoid cyctic carcinoma, mucoepidermoid carcinoma, adenosquamous carcinoma, sarcoma, melanoma, plasmacytoma, verrucous carcinoma, and oat cell (small cell) carcinoma; stomach cancers such as but not limited to, adenocarcinoma, fungating (polypoid), ulcerating, superficial spreading, diffusely spreading, malignant lymphoma, liposarcoma, fibrosarcoma, and carcinosarcoma; colon cancers; rectal cancers; liver cancers such as but not limited to hepatocellular carcinoma and hepatoblastoma, gallbladder cancers such as adenocarcinoma; cholangiocarcinomas such as but not limited to pappillary, nodular, and diffuse; lung cancers such as non-small cell lung cancer (NSCLC), squamous cell carcinoma (epidermoid carcinoma), adenocarcinoma, large-cell carcinoma and small-cell lung cancer (SCLC); testicular cancers such as but not limited to germinal tumor, seminoma, anaplastic, classic (typical), spermatocytic, nonseminoma, embryonal carcinoma, teratoma carcinoma, choriocarcinoma (yolk-sac tumor), prostate cancers such as but not limited to, adenocarcinoma, leiomyosarcoma, and rhabdomyosarcoma; genital cancers such as penile cancer; oral cancers such as but not limited to squamous cell carcinoma; basal cancers; salivary gland cancers such as but not limited to adenocarcinoma, mucoepidermoid carcinoma, and adenoidcystic carcinoma; pharynx cancers such as but not limited to squamous cell cancer, and verrucous; skin cancers such as but not limited to, basal cell carcinoma, squamous cell carcinoma and melanoma, superficial spreading melanoma, nodular melanoma, lentigo malignant melanoma, acral lentiginous melanoma; kidney cancers such as but not limited to renal cell cancer, Clear cell renal cell carcinoma, adenocarcinoma, hypernephroma, fibrosarcoma, transitional cell cancer (renal pelvis and/or ureter); Wilms' tumor; bladder cancers such as but not limited to transitional cell carcinoma, squamous cell cancer, adenocarcinoma, carcinosarcoma. In addition, cancers include myxosarcoma, osteogenic sarcoma, endotheliosarcoma, lymphangioendotheliosarcoma, mesothelioma, synovioma, hemangioblastoma, epithelial carcinoma, cystadenocarcinoma, bronchogenic carcinoma, sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma and papillary adenocarcinomas. Preferably, the cancer is selected from breast, melanoma, prostate, ovarian, colorectal, lung or glioma cancer. More preferably, the cancer is metastatic breast or lung cancer. The targeting and treatment of circulating tumour cells is envisaged.

The treatment of metastatic cancer depends on where the primary tumour is located. When breast cancer spreads to the lungs, for example, it remains a breast cancer and the treatment is determined by the metastatic cancer origin within the breast, not by the fact that it is now in the lung. About 5 percent of the time, metastatic cancer is discovered but the primary tumour cannot be identified. The treatment of these metastatic cancers is dictated by their location rather than their origin. Metastatic cancers are named by the tissue of the original tumour (if known). For example, a breast cancer that has spread to the brain is called metastatic breast cancer to the brain.

Anti-Axl treatment in accordance with the present invention may be used to provide clear benefit for patients with conditions where Axl is overexpressed, or wherein Axl antagonism will provide a clinical benefit. Treatment may be given by injection (e.g. intravenously) or by local delivery methods. The antibody as provided may be used to direct the delivery of pharmaceutical compositions to the target tissue, or systemically in order to target, for example, Circulating Tumour Cells (CTCs) or other metastatic cells.

In a further aspect of the invention, there is provided a method of inhibiting Cancer Stem Cells in a subject, the method comprising of contacting the subject with an antibody (or conjugate thereof) as described herein. Antibodies and conjugates for use in such a method are also envisaged.

EGFR Antagonism

The invention also provides methods of inhibiting constitutive Axl activation comprising administering to the individual an effective amount of any of the anti-Axl antibodies disclosed herein to inhibit constitutive Axl.

In one aspect, the invention provides methods for treating a subject suffering from a cancer associated with an EGFR activating mutation or an EGFR gene amplification, wherein the subject has developed a resistance to treatment with an EGFR antagonist, comprising determining whether the subject has Axl expression, an Axl activating mutation or an Axl gene amplification, and administering to those subjects having an Axl activating mutation or an Axl gene amplification an EGFR antagonist and any of the anti-Axl antibodies described herein.

In one aspect, the invention provides methods for treating a subject suffering from a cancer associated with an EGFR activating mutation or an EGFR gene amplification, comprising: (i) monitoring a subject being treated with an EGFR antagonist to determine if the subject develops Axl expression, an Axl activating mutation or an Axl gene amplification, and (ii) modifying the treatment regimen of the subject to include any of the anti-Axl antibodies described herein in addition to the EGFR antagonist where the subject has developed an Axl activating mutation or an Axl gene amplification.

In one aspect, the invention provides methods for treating a subject suffering from a cancer associated with an EGFR activating mutation or an EGFR gene amplification, comprising: (i) monitoring a subject being treated with EGFR antagonist to determine if the subject develops a resistance to the inhibitor, (ii) testing the subject to determine whether the subject has Axl expression, an Axl activating mutation or an Axl gene amplification, and (iii) modifying the treatment regimen of the subject to include any of the anti-Axl antibodies described herein in addition to the EGFR antagonist where the subject has an Axl activating mutation or an Axl gene amplification.

In one aspect, the invention provides methods for evaluating an EGFR antagonist, comprising: (i) monitoring a population of subjects being treated with an EGFR antagonist to identify those subjects that develop a resistance to the therapeutic, (ii) testing the resistant subjects to determine whether the subjects have Axl expression, an Axl activating mutation or an Axl gene amplification, and (iii) modifying the treatment regimen of the subjects to include any of the anti-Axl antibodies described herein in addition to the EGFR antagonist where the subjects have Axl expression, an Axl activating mutation or an Axl gene amplification.

In one aspect, the invention provides methods for reducing EGFR phosphorylation in a cancer cell, wherein said cancer cell has acquired resistance to an EGFR antagonist, and wherein said cell comprises an Axl activating mutation or an Axl gene amplification, comprising the step of contacting the cell with any of the anti-Axl antibodies described herein and an EGFR antagonist.

In one aspect, the invention provides methods for reducing PBK mediated signaling in a cancer cell, wherein said cancer cell has acquired resistance to an EGFR antagonist, and wherein said cell comprises Axl expression, an Axl activating mutation or an Axl gene amplification, comprising the step of contacting the cell with any of the anti-Axl antibodies described herein and an EGFR antagonist.

In one aspect, the invention provides methods for reducing EGFR-mediated signaling in a cancer cell, wherein said cancer cell has acquired resistance to an EGFR antagonist, and wherein said cell comprises Axl expression, an Axl activating mutation or an Axl gene amplification, comprising contacting the cell with any of the anti-Axl antibodies described herein and an EGFR antagonist.

In one aspect, the invention provides methods for restoring sensitivity of a cancer cell to an EGFR antagonist, wherein said cancer cell has acquired resistance to an EGFR antagonist, and wherein said cell comprises Axl expression, an Axl activating mutation or an Axl gene amplification, comprising contacting the cell with any of the anti-Axl antibodies described herein and an EGFR antagonist.

In one aspect, the invention provides methods for reducing growth or proliferation of a cancer cell, wherein said cancer cell has acquired resistance to an EGFR antagonist, and wherein said cell comprises Axl expression, an Axl activating mutation or an Axl gene amplification, comprising the step of contacting the cell with any of the anti-Axl antibodies described herein and an EGFR antagonist.

In one aspect, the invention provides methods for increasing apoptosis of a cancer cell, wherein said cancer cell has acquired resistance to an EGFR antagonist, and wherein said cell comprises Axl expression, an Axl activating mutation or an Axl gene amplification, comprising the step of contacting the cell with any of the anti-Axl antibodies described herein and an EGFR antagonist.

In one aspect, the invention provides methods for reducing resistance of a cancer cell to an EGFR antagonist, wherein said cancer cell has acquired resistance to an EGFR antagonist, and wherein said cell comprises an Axl activating mutation or an Axl gene amplification, comprising the step of contacting the cell with any of the anti-Axl antibodies described herein and an EGFR antagonist.

In one aspect, the invention provides methods for treating acquired EGFR antagonist resistance in a cancer cell, wherein said cell comprises an Axl activating mutation or an Axl gene amplification, comprising contacting the cell with any of the anti-Axl antibodies described herein and an EGFR antagonist.

In some embodiments, the cancer cell is any EGFR-driven cancer. In some embodiments, the cancer cell comprises an EGFR activating mutation. In some embodiments, the cancer cell comprises an EGFR gene amplification. In some embodiments, the EGFR gene amplification is at least 2-fold. In some embodiments, the Axl amplification is at least 2-fold. In some embodiments, the cancer cell comprises an EGFR gene mutation associated with increased resistance to an EGFR antagonist. In some embodiments, the EGFR gene mutation associated with increased resistance to an EGFR antagonist is a T790M mutation of EGFR.

In some embodiments, the EGFR antagonist is a small molecule therapeutic, a nucleic acid therapeutic, or a protein therapeutic. In some embodiments, the EGFR antagonist is an antibody, an antisense molecule, or a small molecule kinase inhibitor. In some embodiments, the EGFR antagonist is an EGFR kinase inhibitor selected from the group consisting of: gefitinib, erlotinib, cetuximab, panitumumab. In some embodiments, the EGFR antagonist is an anti-EGFR antibody selected from the group consisting of: cetuximab, panitumumab. In some embodiments, the nucleic acid therapeutic is a siRNA molecule.

In one aspect, the invention provides methods for identifying a subject as a candidate for treatment with an EGFR antagonist and any of the anti-Axl antibodies described herein, wherein said subject has been treated with an EGFR antagonist and suffers from cancer that has acquired resistance to said EGFR antagonist, comprising detecting Axl expression, an Axl activating mutation or Axl gene amplification in a cancer cell from said subject.

In one aspect, the invention provides methods for identifying a subject who is being treated with an EGFR antagonist and who is at risk for acquiring resistance to said EGFR antagonist, comprising detecting the presence of Axl expression, an Axl activating mutation or an Axl gene amplification in a cancer cell from said subject, wherein the presence of said Axl expression, Axl activating mutation or Axl gene amplification indicates a risk for acquiring said resistance.

In one aspect, the invention provides methods for treating a subject suffering from a cancer that is resistant to treatment with an EGFR antagonist, comprising administering to the subject an EGFR antagonist and any of the anti-Axl antibodies described herein.

In one aspect, the invention provides methods for treating a subject suffering from a cancer associated with an EGFR activating mutation or an EGFR gene amplification, wherein the subject has developed a resistance to treatment with an EGFR antagonist, comprising determining whether the subject has Axl expression, such as elevated Axl levels and/or activity, and administering to those subjects having Axl expression, such as elevated Axl activity an EGFR antagonist and any of the anti-Axl antibodies described herein.

In one aspect, the invention provides methods for treating a subject suffering from a cancer associated with an EGFR activating mutation or an EGFR gene amplification, comprising: (i) monitoring a subject being treated with an EGFR antagonist to determine if the subject develops Axl expression, such as elevated levels and/or Axl activity, and (ii) modifying the treatment regimen of the subject to include any of the anti-Axl antibodies described herein in addition to the EGFR antagonist where the subject has developed Axl expression, such as elevated Axl levels and/or activity.

In one aspect, the invention provides methods for treating a subject suffering from a cancer associated with an EGFR activating mutation or an EGFR gene amplification, comprising: (i) monitoring a subject being treated with EGFR antagonist to determine if the subject develops a resistance to the inhibitor, (ii) testing the subject to determine whether the subject has Axl expression, such as elevated Axl levels and/or activity, and (iii) modifying the treatment regimen of the subject to include any of the anti-Axl antibodies described herein in addition to the EGFR antagonist where the subject has elevated Axl levels and/or activity.

In another aspect, the invention provides a method for (i) restoring the sensitivity of a cancer cell to an EGFR antagonist, (ii) reducing resistance of a cancer cell to an EGFR antagonist, and/or (iii) treating acquired EGFR antagonist resistance in a cancer cell, by contacting the cell with an EGFR antagonist and any of the anti-Axl antibodies described herein.

In exemplary embodiments, the cancer cell has acquired a resistance to an EGFR antagonist and comprises elevated levels of Axl activity and/or expression, e.g., associated with an activating mutation in the Axl gene, an Axl gene amplification, or Gas6 mediated Axl activation. The methods disclosed herein may be used to restore the sensitivity, reduce the resistance, and/or treat an acquired resistance, of a cancer cell.

In another aspect, the invention provides a method for reducing growth and/or proliferation of a cancer cell, or increasing apoptosis of a cancer cell, by contacting the cell with an EGFR antagonist and any of the anti-Axl antibodies described herein. In exemplary embodiments, the cancer cell has acquired a resistance to an EGFR antagonist and comprises elevated Axl activity and/or expression, e.g., associated with an activating mutation in the Axl gene, an Axl gene amplification, or Gas6 mediated Axl activation.

Pharmaceutical Compositions

Antibodies of the present invention will usually be administered in the form of a pharmaceutical composition, that may comprise at least one component in addition to the antibody.

Thus pharmaceutical compositions according to the present invention, and for use in accordance with the present invention, may comprise, in addition to active ingredient, a pharmaceutically acceptable excipient, carrier, buffer, stabiliser or other materials well known to those skilled in the art. Such materials should be non-toxic and should not interfere with the efficacy of the active ingredient. The precise nature of the carrier or other material will depend on the route of administration, which may be oral, or by injection, e.g. intravenous. The pharmaceutical compositions may be for human or animal usage in human and veterinary medicine.

Examples of such suitable excipients for the various different forms of pharmaceutical compositions described herein may be found in the “Handbook of Pharmaceutical Excipients”, 2nd Edition, (1994), Edited by A Wade and P J Weller.

Acceptable carriers or diluents for therapeutic use are well known in the pharmaceutical art, and are described, for example, in Remington's Pharmaceutical Sciences, Mack Publishing Co. (A. R. Gennaro edit. 1985). Examples of suitable carriers include lactose, starch, glucose, methylcellulose, magnesium stearate, mannitol, sorbitol and the like. Examples of suitable diluents include ethanol, glycerol, water and buffered saline.

The choice of pharmaceutical carrier, excipient or diluent can be selected with regard to the intended route of administration and standard pharmaceutical practice. The pharmaceutical compositions may comprise as, or in addition to, the carrier, excipient or diluent any suitable binder(s), lubricant(s), suspending agent(s), coating agent(s), solubilising agent(s), buffer(s), flavouring agent(s), surface active agent(s), thickener(s), preservative(s) (including antioxidants) and the like, and substances included for the purpose of rendering the formulation isotonic with the blood of the intended recipient.

Examples of suitable binders include starch, gelatine, natural sugars such as glucose, anhydrous lactose, free-flow lactose, beta-lactose, corn sweeteners, natural and synthetic gums, such as acacia, tragacanth or sodium alginate, carboxymethyl cellulose and polyethylene glycol.

Examples of suitable lubricants include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Preservatives, stabilizers, dyes and even flavouring agents may be provided in the pharmaceutical composition. Examples of preservatives include sodium benzoate, sorbic acid and esters of p hydroxybenzoic acid. Antioxidants and suspending agents may be also used.

Pharmaceutical formulations include those suitable for oral, topical (including dermal, buccal and sublingual), rectal or parenteral (including subcutaneous, intradermal, intramuscular and intravenous), nasal and pulmonary administration, e.g., by inhalation. The formulation may, where appropriate, be conveniently presented in discrete dosage units and may be prepared by any of the methods well known in the art of pharmacy. All methods include the step of bringing into association an active compound with liquid carriers or finely divided solid carriers or both and then, if necessary, shaping the product into the desired formulation. Pharmaceutical formulations suitable for oral administration wherein the carrier is a solid are most preferably presented as unit dose formulations such as boluses, capsules or tablets each containing a predetermined amount of active agent. A tablet may be made by compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine an active agent in a free-flowing form such as a powder or granules optionally mixed with a binder, lubricant, inert diluent, lubricating agent, surface-active agent or dispersing agent. Moulded tablets may be made by moulding an active agent with an inert liquid diluent. Tablets may be optionally coated and, if uncoated, may optionally be scored. Capsules may be prepared by filling an active agent, either alone or in admixture with one or more accessory ingredients, into the capsule shells and then sealing them in the usual manner. Cachets are analogous to capsules wherein an active agent together with any accessory ingredient(s) is sealed in a rice paper envelope. An active agent may also be formulated as dispersible granules, which may for example be suspended in water before administration, or sprinkled on food. The granules may be packaged, e.g., in a sachet. Formulations suitable for oral administration wherein the carrier is a liquid may be presented as a solution or a suspension in an aqueous or non-aqueous liquid, or as an oil-in-water liquid emulsion.

Formulations for oral administration include controlled release dosage forms, e.g., tablets wherein an active agent is formulated in an appropriate release—controlling matrix, or is coated with a suitable release—controlling film. Such formulations may be particularly convenient for prophylactic use.

Pharmaceutical formulations suitable for rectal administration wherein the carrier is a solid are most preferably presented as unit dose suppositories. Suitable carriers include cocoa butter and other materials commonly used in the art. The suppositories may be conveniently formed by admixture of an active agent with the softened or melted carrier(s) followed by chilling and shaping in moulds.

Pharmaceutical formulations suitable for parenteral administration include sterile solutions or suspensions of an active agent in aqueous or oleaginous vehicles.

Injectable preparations may be adapted for bolus injection or continuous infusion. Such preparations are conveniently presented in unit dose or multi-dose containers that are sealed after introduction of the formulation until required for use. Alternatively, an active agent may be in powder form which is constituted with a suitable vehicle, such as sterile, pyrogen-free water, before use.

An active compound may also be formulated as long-acting depot preparations, which may be administered by intramuscular injection or by implantation, e.g., subcutaneously or intramuscularly. Depot preparations may include, for example, suitable polymeric or hydrophobic materials, or ion-exchange resins. Such long-acting formulations are particularly convenient for prophylactic use.

Formulations suitable for pulmonary administration via the buccal cavity are presented such that particles containing an active compound and desirably having a diameter in the range of 0.5 to 7 microns are delivered in the bronchial tree of the recipient. As one possibility such formulations are in the form of finely comminuted powders which may conveniently be presented either in a pierceable capsule, suitably of, for example, gelatin, for use in an inhalation device, or alternatively as a self-propelling formulation comprising an active agent, a suitable liquid or gaseous propellant and optionally other ingredients such as a surfactant and/or a solid diluent. Suitable liquid propellants include propane and the chlorofluorocarbons, and suitable gaseous propellants include carbon dioxide. Self-propelling formulations may also be employed wherein an active agent is dispensed in the form of droplets of solution or suspension.

Such self-propelling formulations are analogous to those known in the art and may be prepared by established procedures. Suitably they are presented in a container provided with either a manually-operable or automatically functioning valve having the desired spray characteristics; advantageously the valve is of a metered type delivering a fixed volume, for example, 25 to 100 microliters, upon each operation thereof.

As a further possibility, an active agent may be in the form of a solution or suspension for use in an atomizer or nebuliser whereby an accelerated airstream or ultrasonic agitation is employed to produce a fine droplet mist for inhalation.

Formulations suitable for nasal administration include preparations generally similar to those described above for pulmonary administration. When dispensed such formulations should desirably have a particle diameter in the range 10 to 200 microns to enable retention in the nasal cavity; this may be achieved by, as appropriate, use of a powder of a suitable particle size or choice of an appropriate valve. Other suitable formulations include coarse powders having a particle diameter in the range 20 to 500 microns, for administration by rapid inhalation through the nasal passage from a container held close up to the nose, and nasal drops comprising 0.2 to 5% w/v of an active agent in aqueous or oily solution or suspension.

Pharmaceutically acceptable carriers are well known to those skilled in the art and include, but are not limited to, 0.1 M and preferably 0.05 M phosphate buffer or 0.8% saline. Additionally, such pharmaceutically acceptable carriers may be aqueous or non-aqueous solutions, suspensions, and emulsions. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate. Aqueous carriers include water, alcoholic/aqueous solutions, emulsions or suspensions, including saline and buffered media. Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's or fixed oils. Preservatives and other additives may also be present, such as, for example, antimicrobials, antioxidants, chelating agents, inert gases and the like.

Formulations suitable for topical formulation may be provided for example as gels, creams or ointments. Such preparations may be applied e.g. to a wound or ulcer either directly spread upon the surface of the wound or ulcer or carried on a suitable support such as a bandage, gauze, mesh or the like which may be applied to and over the area to be treated.

Liquid or powder formulations may also be provided which can be sprayed or sprinkled directly onto the site to be treated, e.g. a wound or ulcer. Alternatively, a carrier such as a bandage, gauze, mesh or the like can be sprayed or sprinkle with the formulation and then applied to the site to be treated.

According to a further aspect of the invention, there is provided a process for the preparation of a pharmaceutical or veterinary composition as described above, the process comprising bringing the active compound(s) into association with the carrier, for example by admixture. In general, the formulations are prepared by uniformly and intimately bringing into association the active agent with liquid carriers or finely divided solid carriers or both, and then if necessary shaping the product. The invention extends to methods for preparing a pharmaceutical composition comprising bringing an agent into association with a pharmaceutically or veterinary acceptable carrier or vehicle.

Administration

The pharmaceutical compositions of the present invention may be adapted for oral, rectal, nasal, intrabronchial, topical (including buccal and sublingual), vaginal or parenteral (including subcutaneous, intramuscular, intravenous, intra-arterial and intradermal), intraperitoneal or intrathecal administration. Preferably, the formulation is an intravenously or subcutaneously administered formulation.

The formulations may conveniently be presented in unit dosage form, i.e., in the form of discrete portions containing a unit dose, or a multiple or sub-unit of a unit dose. By way of example, the formulations may be in the form of tablets and sustained release capsules, and may be prepared by any method well known in the art of pharmacy.

Formulations for oral administration in the present invention may be presented as: discrete units such as capsules, gellules, drops, cachets, pills or tablets each containing a predetermined amount of the active agent; as a powder or granules; as a solution, emulsion or a suspension of the active agent in an aqueous liquid or a non-aqueous liquid; or as an oil-inwater liquid emulsion or a water-in-oil liquid emulsion; or as a bolus etc. Preferably, these compositions contain from 1 to 250 mg and more preferably from 10-100 mg, of active ingredient per dose.

For compositions for oral administration (e.g. tablets and capsules), the term “acceptable carrier” includes vehicles such as common excipients e.g. binding agents, for example syrup, acacia, gelatine, sorbitol, tragacanth, polyvinylpyrrolidone (Povidone), methylcellulose, ethylcellulose, sodium carboxymethylcellulose, hydroxypropyl-methylcellulose, sucrose and starch; fillers and carriers, for example corn starch, gelatine, lactose, sucrose, microcrystalline cellulose, kaolin, mannitol, dicalcium phosphate, sodium chloride and alginic acid; and lubricants such as magnesium stearate, sodium stearate and other metallic stearates, glycerol stearate stearic acid, silicone fluid, talc waxes, oils and colloidal silica. Flavouring agents such as peppermint, oil of wintergreen, cherry flavouring and the like can also be used. It may be desirable to add a colouring agent to make the dosage form readily identifiable. Tablets may also be coated by methods well known in the art.

A tablet may be made by compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active agent in a free flowing form such as a powder or granules, optionally mixed with a binder, lubricant, inert diluent, preservative, surface-active or dispersing agent. Moulded tablets may be made by moulding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent. The tablets may be optionally be coated or scored and may be formulated so as to provide slow or controlled release of the active agent.

Other formulations suitable for oral administration include lozenges comprising the active agent in a flavoured base, usually sucrose and acacia or tragacanth; pastilles comprising the active agent in an inert base such as gelatine and glycerine, or sucrose and acacia; and mouthwashes comprising the active agent in a suitable liquid carrier.

Other forms of administration comprise solutions or emulsions which may be injected intravenously, intra-arterially, intrathecally, subcutaneously, intradermally, intraperitoneally or intramuscularly, and which are prepared from sterile or sterilisable solutions. Injectable forms typically contain between 10-1000 mg, preferably between 10-250 mg, of active ingredient per dose.

The pharmaceutical compositions of the present invention may also be in form of suppositories, pessaries, suspensions, emulsions, lotions, ointments, creams, gels, sprays, solutions or dusting powders.

An alternative means of transdermal administration is by use of a skin patch. For example, the active ingredient can be incorporated into a cream consisting of an aqueous emulsion of polyethylene glycols or liquid paraffin. The active ingredient can also be incorporated, at a concentration of between 1 and 10% by weight, into an ointment consisting of a white wax or white soft paraffin base together with such stabilisers and preservatives as may be required.

Alternative formulation strategies may provide preparations suitable for oral or suppository route. The route of administration may be determined by the physicochemical characteristics of the treatment, by special considerations for the disease, to optimise efficacy or to minimise side-effects.

A further mode of administration employs pre-coating of, or otherwise incorporation into, indwelling devices, for which the optimal amount of antibody will be determined by means of appropriate experiments.

An antibody molecule in some preferred embodiments of the invention is a monomeric fragment, such as Fab or scFv. Such antibody fragments may have the feature of a relatively short half-life.

Dosage

A person of ordinary skill in the art can easily determine an appropriate dose of one of the instant compositions to administer to a subject without undue experimentation. Typically, a physician will determine the actual dosage which will be most suitable for an individual patient and it will depend on a variety of factors including the activity of the specific agent employed, the metabolic stability and length of action of that agent, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the individual undergoing therapy.

In accordance with the present invention, compositions provided may be administered to individual patients. Administration is preferably in a “therapeutically effective amount”, this being sufficient to show benefit to a patient. Such benefit may be at least amelioration of at least one symptom. The actual amount administered, and the rate and time-course of administration, will depend on the nature and severity of what is being treated. Prescription of treatment, e.g., decisions on dosage etc., is within the responsibility of general practitioners and other medical doctors. Appropriate doses of antibody are well known in the art; see Ledermann J. A. et al. (1991) Int. J. Cancer 47: 659-664; Bagshawe, K. D. et al. (1991) Antibody, Immunoconjugates and Radiopharmaceuticals 4: 915-922.

The precise dose will depend upon a number of factors, including whether the antibody is for diagnosis or for treatment, the size and location of the area to be treated, the precise nature of the antibody (e.g. whole antibody, antibody fragment or diabody), and the nature of any detectable label or other molecule attached to the antibody. A typical antibody dose may be administered as a bolus intravenously. Other modes of administration include intravenous infusion over several hours, to achieve a similar total cumulative dose. This is a dose for a single treatment of an adult patient, which may be proportionally adjusted for children and infants, and also adjusted for other antibody formats in proportion to molecular weight. Treatments may be repeated at daily, twice-weekly, weekly or monthly intervals, at the discretion of the physician.

The dosages disclosed herein are exemplary of the average case. There can of course be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention.

In accordance with this invention, an effective amount of agent may be administered to inhibit Axl. Of course, this dosage amount will further be modified according to the type of administration of the agent. For example, to achieve an “effective amount” for acute therapy, parenteral administration is preferred. An intravenous infusion of the compound in 5% dextrose in water or normal saline, or a similar formulation with suitable excipients, is most effective, although an intramuscular bolus injection is also useful. Typically, the parenteral dose will be about 0.01 to about 100 mg/kg; preferably between 0.1 and 20 mg/kg, in a manner to maintain the concentration of drug in the plasma at a concentration effective to inhibit a kinase or saturate the target receptor. The agents may be administered one to four times daily at a level to achieve a total daily dose of about 0.4 to about 400 mg/kg/day. The precise amount of an active agent that is therapeutically effective, and the route by which such agent is best administered, is readily determined by one of ordinary skill in the art by comparing the blood level of the agent to the concentration required to have a therapeutic effect.

The agents of this invention may also be administered orally to the patient, in a manner such that the concentration of drug is sufficient to achieve one or more of the therapeutic indications disclosed herein. Typically, a pharmaceutical composition containing the agent is administered at an oral dose of between about 0.1 to about 50 mg/kg in a manner consistent with the condition of the patient. Preferably, the oral dose would be about 0.5 to about 20 mg/kg.

The agents of this invention may be tested in one of several biological assays to determine the concentration of an agent that is required to have a given pharmacological effect.

Combination Therapy

The anti-Axl antibodies of the invention may be administered alone or in combination with other treatments, either simultaneously or sequentially dependent upon the condition to be treated. For example, the antibodies of the invention or conjugates thereof may be used as an anti-cancer monotherapy or in combination therapy with other cancer treatments as mentioned below. Other treatments may include the administration of suitable doses of pain relief drugs such as non-steroidal anti-inflammatory drugs (e.g. aspirin, ibuprofen or ketoprofen) or opiates such as morphine, or anti-emetics.

Suitable Agents for Use in Combination Therapy

These include alkylating agents, e.g., alkyl sulfonates such as busulfan; nitrogen mustards such as chlorambucil, cyclophosphamide, estramustine, ifosfamide, mechlorethamine, melphalan, and uramustine, ethyleneimine derivatives such as thiotepa; nitrosoureas such as carmustine, lomustine, and streptozocin, triazenes such as dacarbazine, procarbazine, and temozolamide; platinum compounds such as cisplatin, carboplatin, oxaliplatin, satraplatin, and picoplatin onnaplatin, tetraplatin, sprioplatin, iproplatin, chloro(diethylenediamino)-platinum (II) chloride, dichloro(ethylenediamino)-platinum (II), diamino(2-ethylmalonato)platinum (II), (1,2-diaminocyclohexane)malonatoplatinum (II), (4-carboxyphthalo)-(1,2-diaminocyclohexane)platinum (II), (1,2-diaminocyclohexane)-(isocitrato)platinum (II), and (1,2-diaminocyclohexane)-cis-(pyruvato)platinum (II); anti-metabolites, including antifolates such as methotrexate, permetrexed, raltitrexed, and trimetrexate; pyrimidine analogs such as azacitidine, capecitabine, cytarabine, edatrexate, floxuridine, fluorouracil, gemcitabine, and troxacitabine; purine analogs such as cladribine, chlorodeoxyadenosine, clofarabine, fludarabine, mercaptopurine, pentostatin, and thioguanine; natural products, including antitumor antibiotics such as bleomycin, dactinomycin, mithramycin, mitomycin, mitoxantrone, porfiromycin, and anthracyclines such as daunorubicin, doxorubicin, epirubicin, idarubicin, and valrubicin; mitotic inhibitors such as the vinca alkaloids vinblastine, vinvesir, vincristine, vindesine, and vinorelbine; enzymes such as L-asparaginase and PEG-L-asparaginase; microtubule polymer stabilizers such as the taxanes paclitaxel and docetaxel; topoisomerase I inhibitors such as the camptothecins irinotecan and topotecan; topoisomerase II inhibitors such as podophyllotoxin, amsacrine, etoposide, teniposide, losoxantrone and actinomycin; hormones and hormone antagonists, including androgens such as fluoxymesterone and testolactone, anti-androgens such as bicalutamide, cyproterone, flutamide, and nilutamide; corticosteroids such as dexamethasone and prednisone; aromatase inhibitors such as aminoglutethimide, anastrozole, exemestane, formestane, and letrozole; estrogens such as diethylstilbestrol; anti-estrogens such as fulvestrant, raloxifene, tamoxifen, and toremifine; luteinising hormone-releasing hormone (LHRH) agonists and antagonists such as abarelix, buserelin, goserelin, leuprolide, histrelin, desorelin, nafarelin acetate and triptorelin; progestins such as medroxyprogesterone acetate and megestrol acetate, and thyroid hormones such as levothyroxine and liothyronine; PKB pathway inhibitors, including perifosine, enzastaurin hydrochloride, and triciribine; PI3K inhibitors such as semaphore and SF1126; mTOR inhibitors such as rapamycin and analogues; CDK inhibitors, including seliciclib, alvocidib, and 7-hydroxystaurosporine; COX-2 inhibitors, including celecoxib; HDAC inhibitors, including trichostatin A, suberoylanilide hydroxamic acid, and chlamydocin; DNA methylase inhibitors, including temozolomide; and miscellaneous agents, including altretamine, arsenic trioxide, thalidomide, lenalidomide, gallium nitrate, levamisole, mitotane, hydroxyurea, octreotide, procarbazine, suramin, photodynamic compounds such as methoxsalen and sodium porfimer, and proteasome inhibitors such as bortezomib.

Molecular targeted therapy agents including: functional therapeutic agents, e.g., gene therapy agents; antisense therapy agents; tyrosine kinase inhibitors such as erlotinib hydrochloride, gefitinib, imatinib mesylate, and semaxanib; RAF inhibitors such as sorafenib; gene expression modulators such as the retinoids and rexinoids, for example adapalene, bexarotene, trans-retinoic acid, 9-cis-retinoic acid, and N-(4-hydroxyphenyl)retinamide; phenotype-directed therapy agents, including monoclonal antibodies such as alemtuzumab, bevacizumab, cetuximab, ibritumomab tiuxetan, rituximab, and trastuzumab; immunotoxins such as emtansine, radioimmunoconjugates such as 1-tositumobab, and cancer vaccines.

Biologic therapy agents including: interferons such as interferon-[alpha]2a and interferon-[alpha]2b, and interleukins such as aldesleukin, denileukin diftitox, and oprelvekin. Axl inhibiting agents including 1-(6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-c]pyridazin-3-yl)-N3-((7-(S)-pyrrolidin-1-yl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-2-yl)-1H-1,2,4-triazole-3,5-diamine (BGB324/R428), CH5451098 (Roche) and Axl inhibitors described in PCT/US07/089177, PCT/US2010/021275 and PCT/EP2011/004451, incorporated herein by reference.

In addition to these agents intended to act against cancer cells, anticancer therapies include the use of protective or adjunctive agents, including: cytoprotective agents such as amifostine, and dexrazoxane; phosphonates such as pamidronate and zoledronic acid; and stimulating factors such as epoetin, darbeopetin, filgrastim, PEG-filgrastim, and sargramostim.

Many combination chemotherapeutic regimens are known to the art, such as combinations of carboplatin/paclitaxel, capecitabine/docetaxel, fluorauracil/levamisole, fluorauracil/leucovorin, methotrexate/leucovorin, and trastuzumab/paclitaxel, alone or in further combination with carboplatin, and the like.

A particularly preferred class of agent for use in combination with the anti-Axl antibodies disclosed herein are Immune Checkpoint Modulators (ICMs) such as Immune Checkpoint Inhibitors (ICls).

Immune checkpoints, which are inhibitory pathways in the immune system, may be co-opted by tumours to induce immune resistance. The use of antibodies to block or modulate immune checkpoints, including T-cell stimulatory and inhibitory receptors and dendritic cell stimulatory receptors, and thus to reduce or reverse the immune resistance of the cancer, is thus an important avenue in cancer research.

T-cell stimulatory receptors that may be modulated through the use of immune 35 checkpoint modulating antibodies include CD28, ICOS, 4-1BB, OX40, GITR, CD27, TWEAKR, HVEM and TIM-1. T-cell inhibitory receptors that maybe modulated through the use of immune checkpoint modulating antibodies include PD-L1, CTLA-4, PD-1, BTLA, TIM-3, VISTA, LAG-3 and TIGIT. Dendritic cell stimulatory receptors that may be modulated through the use of immune checkpoint modulating antibodies include CD40 and 4-1BB.

Thus ICMs suitable for use in combination with the anti-Axl antibodies disclosed herein include the immune checkpoint modulating, or inhibiting, antibodies of which there are many known in the art. Particularly suitable immune checkpoint modulating antibodies include:

-   -   CTLA-4 targeting antibodies, including Ipilimumab and         Tremelimumab.     -   PD-1 targeting antibodies, including Pembrolizumab, Mivolumab         and AMP514/MEDI0680.     -   BD-L1 targeting antibodies, including MPDL3280A, MEDI4736,         MSB0010718C and BMS-936559.     -   4-1E targeting antibodies, including Urelumab and PF-05082566.     -   OX-40 targeting antibodies, including MEDI6469, MEDI6383         (rOX40L) and MOXR0916.     -   GITR targeting antibodies, including TRX518.     -   CD27 targeting antibodies, including CDX-1127.     -   CD40 targeting antibodies, including CP-870,893.     -   LAG3 targeting antibodies, including BMS-986016.

Where a combination of ICM antibodies are used in conjunction with an anti-AXL antibody of the invention, all of the ICM antibodies used may target inhibitory receptors, all of the ICM antibodies used may target stimulatory receptors, or a combination of inhibitory receptor and stimulatory receptor targeting ICM antibodies may be used.

The disclosure therefore provides an antibody that binds Axl, as described herein, for use in treatment (of, for example, a proliferative disease such as cancer), wherein the treatment further comprises one or more immune checkpoint modulating antibodies. Likewise, there is provided an antibody that binds Axl, as described herein, in the manufacture of a medicament for the treatment of a proliferative disease (such as cancer), wherein the treatment further comprises one or more immune checkpoint modulating antibodies. The antibodies may be selected from Ipilimumab, Tremelimumab, Pembrolizumab, Mivolumab, AMP-514/MEDI0680, MPDL3280A, MEDI4736, MSB0010718C, BMS-936559, Urelumab, PF-05082566, MEDI6469, MEDI6383 (rOX40L), MOXR0916, TRX518, CDX-1127, CP-870,893 and BMS-986016. The cancer may be selected from lung cancer, melanoma, breast cancer, ovarian cancer or carcinoma.

The compound of the invention may be administered before the one or more immune checkpoint modulating antibodies, simultaneously with the one or more immune checkpoint modulating antibodies, or after the one or more immune checkpoint modulating antibodies.

Another particularly preferred class of agent for use in combination with the anti-Axl antibodies of the present invention are anti-tumour antibodies specific for a target other than Axl. Such antibodies suitable for use in combination with the anti-Axl antibodies of the present invention are set out in the table below:

Examples of therapeutic Antigen Examples of mAbs raised against Tumour types expressing category antigens these targets antigen Haematopoietic CD20 Rituximab Non-Hodgkin's lymphoma differentiation Ibritumomab tiuxetan and Lymphoma antigens tositumomab CD30 Brentuximab vedotin Hodgkin's lymphoma CD33 Gemtuzumab ozogamicin Acute myelogenous leukaemia CD52 Alemtuzumab Chronic lymphocytic leukaemia Glycoproteins EpCAM IGN101 and Epithelial tumours (breast, expressed by adecatumumab colon and lung) solid tumours CEA Labetuzumab Breast, colon and lung tumours gpA33 huA33 Colorectal carcinoma Mucins Pemtumomab and Breast, colon, lung and oregovomab ovarian tumours TAG-72 CC49 (minretumomab) Breast, colon and lung tumours CAIX cG250 Renal cell carcinoma PSMA J591 Prostate carcinoma Folate-binding MOv18 and MORAb-003 Ovarian tumours protein (farletuzumab) Glycolipids Gangliosides (such 3F8, ch14.18 and KW- Neuroectodermal tumours and as GD2, GD3 and 2871 some epithelial tumours GM2) Carbohydrates Le^(y) hu3S193 and IgN311 Breast, colon, lung and prostate tumours Targets of anti- VEGF Bevacizumab Tumour vasculature angiogenic VEGFR IM-2C6 and CDP791 Epithelium-derived solid mAbs tumours Integrin αVβ3 Etaracizumab Tumour vasculature Integrin α5β1 Volociximab Tumour vasculature Growth and EGFR Cetuximab, Glioma, lung, breast, colon, differentiation panitumumab, and head and neck tumours signalling nimotuzumab and 806 ERBB2 Trastuzumab and Breast, colon, lung, ovarian pertuzumab and prostate tumours ERBB3 MM-121 Breast, colon, lung, ovarian and prostate, tumours MET AMG 102, METMAB and Breast, ovary and lung tumours SCH 900105 IGF1R AVE1642, IMC-A12, MK- Glioma, lung, breast, head 0646, R1507 and CP and neck, prostate and thyroid 751871 cancer EPHA3 KB004 and IIIA4 Lung, kidney and colon tumours, melanoma, glioma and haematological malignancies TRAILR1 Mapatumumab (HGS- Colon, lung and pancreas ETR1) tumours and haematological malignancies TRAILR2 HGS-ETR2 and CS-1008 RANKL Denosumab Prostate cancer and bone metastases Stromal and FAP Sibrotuzumab and F19 Colon, breast, lung, pancreas, extracellular and head and neck tumours matrix antigens Tenascin 81C6 Glioma, breast and prostate tumours

Throughout the specification, preferably the methods described herein are performed in vitro or ex vivo. Methods can also be performed in vivo.

The present invention provides a method comprising causing or allowing binding of an antibody as provided herein to Axl. As noted, such binding may take place in vivo, e.g. following administration of an antibody, or nucleic acid encoding an antibody, or it may take place in vitro, for example in ELISA, Western blot analysis, immunocytochemistry, immunohistochemistry, immunoprecipitation or affinity chromatography.

The amount of antibody bound to Axl receptor may be determined. Quantitation may be related to the amount of the antigen in a test sample, which may be of diagnostic interest.

The reactivity of antibody in a sample may be determined by any appropriate means. Radioimmunoassay (RIA) is one possibility. Radioactively labelled antigen is mixed with unlabelled antigen (the test sample) and allowed to bind to the antibody. Bound antigen is physically separated from unbound antigen and the amount of radioactive antigen bound to the antibody determined. The more antigen there is in the test sample the less radioactive antigen will bind to the antibody. A competitive binding assay may also be used with non-radioactive antigen, using antigen or an analogue linked to a reporter molecule. The reporter molecule may be a fluorochrome, phosphor or laser dye with spectrally isolated absorption or emission characteristics. Suitable fluorochromes include fluorescein, rhodamine, phycoerythrin and Texas Red. Suitable chromogenic dyes include diaminobenzidine.

Other reporters include macromolecular colloidal particles or particulate material such as latex beads that are coloured, magnetic or paramagnetic, and biologically or chemically active agents that can directly or indirectly cause detectable signals to be visually observed, electronically detected or otherwise recorded. These molecules may be enzymes which catalyse reactions that develop or change colours or cause changes in electrical properties, for example. They may be molecularly excitable, such that electronic transitions between energy states result in characteristic spectral absorptions or emissions. They may include chemical entities used in conjunction with biosensors. Biotin/avidin or biotin/streptavidin and alkaline phosphatase detection systems may be employed.

The signals generated by individual antibody-reporter conjugates may be used to derive quantifiable absolute or relative data of the relevant antibody binding in samples (normal and test).

The present invention also provides the use of an antibody as above for measuring antigen levels in a competition assay, that is to say a method of measuring the level of antigen in a sample by employing an antibody as provided by the present invention in a competition assay. This may be where the physical separation of bound from unbound antigen is not required. Linking a reporter molecule to the antibody so that a physical or optical change occurs on binding is one possibility. The reporter molecule may directly or indirectly generate detectable, and preferably measurable, signals. The linkage of reporter molecules may be directly or indirectly, covalently, e.g. via a peptide bond or non-covalently. Linkage via a peptide bond may be as a result of recombinant expression of a gene fusion encoding antibody and reporter molecule.

The present invention also provides for measuring levels of antigen directly, by employing an antibody according to the invention for example in a biosensor system.

The mode of determining binding is not a feature of the present invention and those skilled in the art are able to choose a suitable mode according to their preference and general knowledge.

The present invention further extends to an antibody that competes for binding to Axl with any antibody that both binds the antigen and comprises an antibody variable domain (either VH or VL or both) including a CDR with amino acid substantially as set out herein or a variable domain with amino acid sequence substantially as set out herein. Competition between the antibodies may be assayed easily in vitro, for example by tagging a specific reporter molecule to one binding member that can be detected in the presence of other untagged binding member(s), to enable identification of antibodies that bind the same epitope or an overlapping epitope. Competition may be determined for example using ELISA or flow cytometry. Alternatively, competing antibodies may be identified via surface plasmon resonase (SPR) technique using Biacore instrument, as described in Example 6.

In another method, to screen for antibodies that bind to the epitope on Axl bound by an antibody of interest (e.g., those that block binding of the 10C9 or 10G5 antibody to Axl), a routine cross-blocking assay such as that described in Antibodies. A Laboratory Manual. Cold Spring Harbor Laboratory. Ed Harlow and David Lane (1988), can be performed.

In testing for competition, a peptide fragment of the antigen may be employed, especially a peptide including an epitope of interest. A peptide having the epitope sequence plus one or more amino acids at either end may be used. Such a peptide may be said to “consist essentially” of the specified sequence. Antibodies according to the present invention may be such that their binding for antigen is inhibited by a peptide with or including the sequence given. In testing for this, a peptide with either sequence plus one or more amino acids may be used.

Antibodies that bind a specific peptide may be isolated for example from a phage display library by panning with the peptide(s).

The present invention further provides an isolated nucleic acid encoding an antibody of the present invention. Nucleic acid includes DNA and RNA. In a preferred aspect, the present invention provides a nucleic acid that codes for a CDR, VH or VL domain of the invention as defined above.

The present invention also provides constructs in the form of plasmids, vectors, transcription or expression cassettes that comprise at least one polynucleotide as above.

The present invention also provides a recombinant host cell that comprises one or more constructs as above. A nucleic acid encoding any CDR, VH or VL domain, or antibody as provided, itself forms an aspect of the present invention, as does a method of production of the encoded product, which method comprises expression from encoding nucleic acid therefor. Expression may conveniently be achieved by culturing under appropriate conditions recombinant host cells containing the nucleic acid. Following production by expression, a VH or VL domain, or antibody may be isolated and/or purified using any suitable technique known in the art.

Antibodies, VH and/or VL domains, and encoding nucleic acid molecules and vectors according to the present invention may be provided isolated and/or purified, e.g. from their natural environment, in substantially pure or homogeneous form, or, in the case of nucleic acid, free or substantially free of nucleic acid or genes of an origin other than the sequence encoding a polypeptide with the required function. Nucleic acid according to the present invention may comprise DNA or RNA and may be wholly or partially synthetic. Reference to a nucleotide sequence as set out herein encompasses a DNA molecule with the specified sequence, and encompasses a RNA molecule with the specified sequence in which U is substituted for T, unless context requires otherwise.

Systems for cloning and expression of a polypeptide in a variety of different host cells are well known. Suitable host cells include bacteria, mammalian cells, yeast, baculovirus, and insect cell systems. Mammalian cell lines available in the art for expression of a heterologous polypeptide include Chinese hamster ovary cells (CHO), HeLa cells, baby hamster kidney (BHK) cells, NS0 and SP2/0 mouse myeloma cells, YB2/0 rat myeloma cells, human cell lines HEK-293 and PER.C6 and many others. A common, preferred bacterial host is E. coli.

The expression of antibodies and antibody fragments in prokaryotic cells such as E. coli is well established in the art. For a review, see for example Plückthun, A. Bio/Technology 9: 545-551 (1991). Expression in eukaryotic cells in culture is also available to those skilled in the art as an option for production of an antibody, see for reviews, for example Ref, M. E. (1993) Curr. Opinion Biotech. 4: 573-576; Trill J. J. et al. (1995) Curr. Opinion Biotech 6: 553-560.

Suitable vectors can be chosen or constructed, containing appropriate regulatory sequences, including promoter sequences, terminator sequences, polyadenylation sequences, enhancer sequences, marker genes and other sequences as appropriate. Vectors may be plasmids, viral e.g. phage, or phagemid, as appropriate (Sambrook and Russell, 2001, Molecular Cloning: a Laboratory Manual: 3^(rd) edition, Cold Spring Harbor Laboratory Press). Many known techniques and protocols for manipulation of nucleic acid, for example in preparation of nucleic acid constructs, mutagenesis, sequencing, introduction of DNA into cells and gene expression, and analysis of proteins, are described in detail in Current Protocols in Molecular Biology, Second Edition, Ausubel et al. eds., John Wiley & Sons, 1992.

Thus, a further aspect of the present invention provides a host cell containing nucleic acid as disclosed herein. A still further aspect provides a method comprising introducing such nucleic acid into a host cell. The introduction may employ any available technique. For eukaryotic cells, suitable techniques may include calcium phosphate transfection, DEAEDextran, electroporation, liposome-mediated transfection and transduction using retrovirus or other virus, e.g. vaccinia or, for insect cells, baculovirus. For bacterial cells, suitable techniques may include calcium chloride transformation, electroporation and transfection using bacteriophage.

The introduction may be followed by causing or allowing expression from the nucleic acid, e.g. by culturing host cells under conditions for expression of the gene.

In one embodiment, the nucleic acid of the invention is integrated into the genome (e.g. chromosome) of the host cell. Integration may be promoted by inclusion of sequences that promote recombination with the genome, in accordance with standard techniques.

The present invention also provides a method that comprises using a construct as stated above in an expression system in order to express an antibody or polypeptide as above.

Aspects and embodiments of the present invention will now be illustrated by way of example with reference to the following experimentation.

All documents cited anywhere in this specification are incorporated by reference.

Statements of Invention—10C9 Antibody

The following paragraphs describe a number of specifically envisioned embodiments and combinations of the present invention.

1. An antibody that binds Axl and which comprises:

-   -   an antibody VH domain selected from the group consisting of the         10C9 VH domain (SEQ ID NO.3) and a VH domain comprising a VH         CDR3 with the amino acid sequence of SEQ ID NO.7 and optionally         one or more VH CDR's with an amino acid sequence selected from         SEQ ID NO.6 and SEQ ID NO.5; and/or     -   an antibody VL domain selected from the group consisting of the         10C9 VL domain (SEQ ID NO. 4) and a VL domain comprising one or         more VL CDR's with an amino acid sequence selected from SEQ ID         NO.8, SEQ ID NO.9 and SEQ ID NO.10.

2. An antibody according to paragraph 1 comprising an antibody VH domain comprising the VH CDR's with the amino acid sequences of SEQ ID NO.5, SEQ ID NO.6 and SEQ ID NO.7, which antibody competes for binding to Axl with an Axl binding domain of an antibody comprising the 10C9 VH domain (SEQ ID NO. 3) and the 10C9 VL domain (SEQ ID NO. 4).

3. An antibody according to paragraph 1 or paragraph 2 comprising the 10C9 VH domain (SEQ ID NO. 3).

4. An antibody according to paragraph 3 comprising the 10C9 VL domain (SEQ ID NO. 4).

5. A variant of an antibody according to any one of paragraphs 1 to 4, wherein the variant comprises one or more amino acid sequence alterations in one or more framework regions and/or one or more CDRs.

6. An antibody according to any one of paragraphs 1 to 5 that binds Axl with affinity equal to or better than the affinity of an Axl antigen-binding site formed by the 10C9 VH domain (SEQ ID NO. 3) and the 10C9 VL domain (SEQ ID NO. 4), the affinity of the antibody and the affinity of the antigen-binding site being as determined under the same conditions.

7. An antibody according to any one of paragraphs 1 to 6 that comprises an scFv antibody molecule.

8. An antibody according to any one of paragraphs 1 to 6 that comprises an antibody constant region.

9. An antibody according to paragraph 8 that comprises a whole antibody.

10. An antibody according to any one of paragraphs 1 to 9 that comprises additional amino acids providing a further functional characteristic in addition to the ability to bind antigen.

11. An antibody according to any one of paragraphs 1 to 10 that binds Axl with a K_(D) no greater than 2×10⁻¹⁰ M.

12. An antibody according to any one of paragraphs 1 to 11 that binds Axl with a k_(on) no lower than 1.5×10⁶ M⁻¹s⁻¹.

13. An antibody according to any one of paragraphs 1 to 12 wherein the Axl is human Axl.

14. An antibody according to any one of paragraphs 1 to 13 that specifically binds primate Axl.

15. An antibody according to any one of paragraphs 1 to 14 that:

-   -   (i) binds murine Axl with a K_(D) greater than 10⁻³ M;     -   (ii) binds human Mer with a K_(D) greater than 10⁻³ M; and/or     -   (iii) binds human Tyro3 with a K_(D) greater than 10⁻³ M.

16. An antibody according to any one of paragraphs 1 to 15 that inhibits the binding of Axl to Gas6.

17. An antibody according to any one of paragraphs 1 to 16 that down-regulates expression of the Axl receptor.

18. An antibody according to paragraph 17, wherein the antibody reduces Axl receptor expression to less than 50% of the level observed in an otherwise identically treated sample that is not contacted with to the antibody.

19. An antibody according to either one of paragraphs 17 or 18, wherein the downregulation of Axl receptor expression is observed within 12 hours of contacting the sample with the antibody.

20. An antibody according to any one of paragraphs 17 to 19, wherein the down regulation of Axl receptor expression persists for at least 24 hours following contacting the sample with the antibody.

21. An antibody according to any one of paragraphs 1 to 20 that increases the rate of Axl receptor internalization.

22. An antibody according to any one of paragraphs 1 to 21 that inhibits Axl activity.

23. An antibody according to paragraph 22, wherein the antibody inhibits Axl receptor downstream signalling.

24. An antibody according to either one of paragraphs 22 or 23 wherein the phosphorylation of Akt at Serine 473 in a sample contacted with the antibody of the invention is less than 50% of the level observed in an otherwise identically treated sample that is not contacted with the antibody

25. An antibody according to any one of paragraphs 1 to 24 that increases the rate of cell death.

26. An antibody according to any one of paragraphs 1 to 25 that inhibits tumour growth.

27. An antibody according to any one of paragraphs 1 to 26 that is conjugated to a detectable label, enzyme, or toxin, optionally via a peptidyl bond or linker.

28. An antibody according to paragraph 27 wherein the toxin is selected from the group comprising MMAE and MMAF.

29. An antibody according to paragraph 27 wherein the detectable label is FITC.

30. An antibody according to any one of paragraphs 1 to 29 binds to the epitope bound by the 10C9 antibody obtainable from the hybridoma UT-10C9-B9.

31. An antibody that binds to the epitope bound by the 10C9 antibody obtainable from the hybridoma UT-10C9-B9.

32. The antibody according to paragraph 31 that inhibits the binding of Axl to its ligand Gas6.

33. The antibody according to either one of paragraphs 31 or 32 that downregulates Axl expression, inhibits Axl receptor signalling, and/or inhibits tumour growth.

34. An 10C9 antibody obtainable from the hybridoma UT-10C9-B9.

35. An isolated nucleic acid that comprises a nucleotide sequence encoding an antibody or antibody VH or VL domain of an antibody according to any one of paragraphs 1 to 26.

36. A host cell transformed with nucleic acid according to paragraph 35.

37. A method of producing an antibody or antibody VH or VL domain, the method comprising culturing host cells according to paragraph 36 under conditions for production of said antibody or antibody VH or VL domain.

38. A method according to paragraph 37 further comprising isolating and/or purifying said antibody or antibody VH or VL variable domain.

39. A method according to paragraph 37 or paragraph 38 further comprising formulating the antibody or antibody VH or VL variable domain into a composition including at least one additional component.

40. A method of obtaining an antibody that binds Axl, the method comprising

-   -   providing by way of addition, deletion, substitution or         insertion of one or more amino acids in the amino acid sequence         of the 10C9 VH domain (SEQ ID NO. 3) one or more VH domains each         of which is an amino acid sequence variant of the 10C9 VH         domain, optionally combining one or more VH domain amino acid         sequence variants thus provided with one or more VL domains to         provide one or more VH/VL combinations; and/or     -   providing by way of addition, deletion, substitution or         insertion of one or more amino acids in the amino acid sequence         of the 10C9 VL domain (SEQ ID NO. 4) a VL domain that is an         amino acid sequence variant of the 10C9 VL domain, and combining         one or more VL domain amino acid sequence variants thus provided         with one or more VH domains to provide one or more VH/VL domain         combinations; and     -   testing the VH domain amino acid sequence variants or VH/VL         combination or combinations for to identify a antibody that         binds Axl.

41. A method of obtaining an antibody that binds Axl, which method comprises:

-   -   providing starting nucleic acids encoding one or more VH domains         that either comprise a CDR3 to be replaced or lack a CDR3         encoding region, and combining said starting nucleic acid with a         donor nucleic acid encoding the VH CDR3 amino acid sequence of         SEQ ID NO.7 such that said donor nucleic acid is inserted into         the CDR3 region in the starting nucleic acid, so as to provide         product nucleic acids encoding VH domains; or     -   providing starting nucleic acids encoding one or more VL domains         that either comprise a CDR3 to be replaced or lack a CDR3         encoding region, and combining said starting nucleic acid with a         donor nucleic acid encoding the VL CDR3 amino acid sequence of         SEQ ID NO.10 such that said donor nucleic acid is inserted into         the CDR3 region in the starting nucleic acid, so as to provide         product nucleic acids encoding VL domains;     -   expressing the nucleic acids of said product nucleic acids         encoding VH domains and optionally combining the VH domains thus         produced with one or more VL domains to provide VH/VL         combinations, and/or expressing the nucleic acids of said         product nucleic acids encoding VL domains and combining the VL         domains thus produced with one or more VH domains to provide         VH/VL combinations;     -   selecting an antibody comprising a VH domain or a VH/VL         combination that binds Axl; and     -   recovering said antibody that binds Axl and/or nucleic acid         encoding the antibody that binds Axl.

42. A method according to paragraph 41 or paragraph 41 wherein the antibody that binds Axl is an antibody fragment comprising a VH domain and a VL domain.

43. A method according to paragraph 42 wherein the antibody fragment is an scFv antibody molecule.

44. A method according to paragraph 42 wherein the antibody fragment is an Fab antibody molecule.

45. A method according to paragraph 43 or paragraph 44 further comprising providing the VH domain and/or the VL domain of the antibody fragment in a whole antibody.

46. A method according to any one of paragraphs 37 to 45 further comprising formulating the antibody that binds Axl or an antibody VH or VL variable domain of the antibody that binds Axl into a composition including at least one additional component.

47. A method according to any one of paragraphs 37 to 46 further comprising binding an antibody that binds Axl to Axl or a fragment of Axl.

48. A method comprising binding an antibody that binds Axl according to any one of paragraphs 1 to 29 to Axl or a fragment of Axl.

49. A method according to paragraph 47 or paragraph 48 wherein said binding takes place in vitro.

50. A method according to any one of paragraphs 47 to 49 comprising determining the amount of binding of antibody to Axl or a fragment of Axl.

51. A method according to any one of paragraphs 37 to 46 further comprising use of the antibody in the manufacture of a medicament for treatment of a disease or disorder characterised by overexpression of Axl.

52. A composition comprising an antibody according to any one of paragraphs 1 to 26, or an immunoconjugate thereof, in conjunction with a pharmaceutically acceptable excipient.

53. The composition according to paragraph 52, further comprising an Immune Checkpoint Modulator, and/or an anti-tumour antibody specific for a target other than Axl.

54. The composition according to paragraph 53, wherein the Immune Checkpoint Modulator is an antibody, such as Ipilimumab, Tremelimumab, Pembrolizumab, Mivolumab, AMP-514/MEDI0680, MPDL3280A, MEDI4736, MSB0010718C, BMS-936559, Urelumab, PF-05082566, MEDI6469, MEDI6383 (rOX40L), MOXR0916, TRX518, CDX-1127, CP-870,893 or BMS-986016.

55. The composition according to paragraph 53, wherein the anti-tumour antibody specific for a target other than Axl is selected from the group consisting of Rituximab, Ibritumomab tiuxetan, tositumomab, Brentuximab vedotin, Gemtuzumab ozogamicin, Alemtuzumab, IGN101, adecatumumab, Labetuzumab, huA33, Pemtumomab, oregovomab, CC49 (minretumomab), cG250, J591, MOv18, MORAb-003 (farletuzumab), 3F8, ch14.18, KW2871, hu3S193, IgN311, Bevacizumab, IM-2C6, CDP791, Etaracizumab, Volociximab, Cetuximab, panitumumab, nimotuzumab 806, Trastuzumab, pertuzumab, MM-121, AMG 102, METMAB, SCH 900105, AVE1642, IMC-A12, MK-0646, R1507, CP 751871, KB004, IllA4, Mapatumumab (HGS-ETR1), HGS-ETR2, CS-1008, Denosumab, Sibrotuzumab, F19, 81C6.

56. An antibody according to any one of paragraphs 1 to 29, or the composition according to any one of paragraphs 52 to 55, for use in a method of treatment.

57. An antibody or composition according to paragraph 56 for use in a method of treating a proliferative disease.

58. An antibody or composition according to paragraph 57 where the proliferative disease is cancer.

59. An antibody or composition according to paragraph 58 where the cancer is metastatic cancer.

60. Use of an antibody according to any one of paragraphs 1 to 29, or the composition according to any one of paragraphs 52 to 55, in the manufacture of a medicament for treatment of a disease or disorder characterised by overexpression of Axl.

61. A method of treatment of a disease or disorder characterised by overexpression of Axl, the method comprising administering an antibody according to any one of paragraphs 1 to 29, or the composition according to any one of paragraphs 52 to 55, to a patient with the disease or disorder or at risk of developing the disease or disorder.

62. An antibody according to any one of paragraphs 56 to 59, or method of claim 61, wherein the method of treatment comprises administering the antibody according to any one of paragraphs 1 to 29, or the composition according to any one of paragraphs 52 to 55, in combination with an Immune Checkpoint Modulator and/or an anti-tumour antibody specific for a target other than Axl.

63. A method according to paragraph 61 wherein the antibody directs the delivery of a pharmaceutical composition to target metastatic cancer cells.

64. Use of an antibody according to any one of paragraphs 1 to 29 and one or more reagents that allow determination of the binding of said antibody to metastatic cancer cells, in the manufacture of a diagnostic agent for the detection of a disease or disorder characterised by overexpression of Axl.

65. A method of diagnosis of a disease or disorder characterised by overexpression of Axl, the method comprising administering an antibody according to any one of paragraphs 1 to 29, or the composition according to any one of paragraphs 52 to 55, and one or more reagents that allow determination of the binding of said antibody to metastatic cancer cells, to a patient with the disease or disorder or at risk of developing the disease or disorder.

66. A diagnostic kit comprising an antibody according to any one of paragraphs 1 to 29 and one or more reagents that allow determination of the binding of said member to metastatic cancer cells.

67. A kit comprising an antibody according to any one of paragraphs 1 to 29, or the composition according to any one of paragraphs 52 to 55.

68. A pharmaceutical composition comprising as active principle an antibody according to paragraphs 1-29 in an effective amount, in conjunction with a pharmaceutically acceptable excipient.

Statements of Invention—10G5 Antibody

The following paragraphs describe a number of specifically envisioned embodiments and combinations of the present invention.

1a. An antibody that binds Axl and which comprises:

-   -   an antibody VH domain selected from the group consisting of the         10G5 VH domain (SEQ ID NO.21) and a VH domain comprising a VH         CDR3 with the amino acid sequence of SEQ ID NO.25 and optionally         one or more VH CDR's with an amino acid sequence selected from         SEQ ID NO.24 and SEQ ID NO.23; and/or     -   an antibody VL domain selected from the group consisting of the         10G5 VL domain (SEQ ID NO. 22) and a VL domain comprising one or         more VL CDR's with an amino acid sequence selected from SEQ ID         NO.26, SEQ ID NO.27 and SEQ ID NO.28.

1b. An antibody that binds Axl and which comprises:

-   -   an antibody VH domain selected from the group consisting of the         10G5(Q1E) VH domain (SEQ ID NO45) and a VH domain comprising a         VH CDR3 with the amino acid sequence of SEQ ID NO.25 and         optionally one or more VH CDR's with an amino acid sequence         selected from SEQ ID NO.24 and SEQ ID NO.23; and/or     -   an antibody VL domain selected from the group consisting of the         10G5 VL domain (SEQ ID NO. 22) and a VL domain comprising one or         more VL CDR's with an amino acid sequence selected from SEQ ID         NO.26, SEQ ID NO.27 and SEQ ID NO.28.

2a. An antibody according to paragraph 1a or 1b comprising an antibody VH domain comprising the VH CDR's with the amino acid sequences of SEQ ID NO.23, SEQ ID NO.24 and SEQ ID NO.25, which antibody competes for binding to Axl with an Axl binding domain of an antibody comprising the 10G5 VH domain (SEQ ID NO. 21) and the 10G5 VL domain (SEQ ID NO. 22).

3a. An antibody according to paragraph 1a or paragraph 2a comprising the 10G5 VH domain (SEQ ID NO. 21).

3b. An antibody according to paragraph 1b or paragraph 2a comprising the 10G5(Q1E) VH domain (SEQ ID NO. 45).

4a. An antibody according to paragraph 3a comprising the 10G5 VL domain (SEQ ID NO. 22)

5a. A variant of an antibody according to any one of paragraphs 1a to 4a, wherein the variant comprises one or more amino acid sequence alterations in one or more framework regions and/or one or more CDRs.

6a. An antibody according to any one of paragraphs 1a to 5a that binds Axl with affinity equal to or better than the affinity of an Axl antigen-binding site formed by the 10G5 VH domain (SEQ ID NO. 21) and the 10G5 VL domain (SEQ ID NO. 22), the affinity of the antibody and the affinity of the antigen-binding site being as determined under the same conditions.

7a. An antibody according to any one of paragraphs 1a to 6a that comprises an scFv antibody molecule.

8a. An antibody according to any one of paragraphs 1a to 6a that comprises an antibody constant region.

9a. An antibody according to paragraph 8a that comprises a whole antibody.

10a An antibody according to any one of paragraphs 1a to 9a that comprises additional amino acids providing a further functional characteristic in addition to the ability to bind antigen.

11a. An antibody according to any one of paragraphs 1a to 10a that binds Axl with a K_(D) no greater than 6×10⁻¹⁰ M.

12a. An antibody according to any one of paragraphs 1a to 11a that binds Axl with a k_(on) no lower than 8×10⁵ M⁻¹s⁻¹.

13a. An antibody according to any one of paragraphs 1a to 12a wherein the Axl is human Axl.

14a. An antibody according to any one of paragraphs 1a to 13a that specifically binds primate Axl.

15a. An antibody according to any one of paragraphs 1a to 14a that:

-   -   (i) binds murine Axl with a K_(D) greater than 10⁻³ M;     -   (ii) binds human Mer with a K_(D) greater than 10⁻³ M; and/or     -   (iii) binds human Tyro3 with a K_(D) greater than 10⁻³ M.

16a. An antibody according to any one of paragraphs 1a to 15a that inhibits the binding of Axl to Gas6.

17a. An antibody according to any one of paragraphs 1a to 16a that downregulates expression of the Axl receptor.

18a. An antibody according to paragraph 17a, wherein the antibody reduces Axl receptor expression to less than 50% of the level observed in an otherwise identically treated sample that is not contacted with to the antibody.

19a. An antibody according to either one of paragraphs 17a or 18a, wherein the downregulation of Axl receptor expression is observed within 12 hours of contacting the sample with the antibody.

20a. An antibody according to any one of paragraphs 17a to 19a, wherein the down regulation of Axl receptor expression persists for at least 24 hours following contacting the sample with the antibody.

21a. An antibody according to any one of paragraphs 1a to 20a that increases the rate of Axl receptor internalization.

22a. An antibody according to any one of paragraphs 1a to 21a that inhibits Axl activity.

23a. An antibody according to paragraph 22a, wherein the antibody inhibits Axl receptor downstream signalling.

24a. An antibody according to either one of paragraphs 22a or 23a wherein the phosphorylation of Akt at Serine 473 in a sample contacted with the antibody of the invention is less than 50% of the level observed in an otherwise identically treated sample that is not contacted with the antibody

25a. An antibody according to any one of paragraphs 1a to 24a that increases the rate of cell death.

26a. An antibody according to any one of paragraphs 1a to 25a that inhibits tumour growth.

27a. An antibody according to any one of paragraphs 1a to 26a that is conjugated to a detectable label, enzyme, or toxin, optionally via a peptidyl bond or linker.

28a. An antibody according to paragraph 27a wherein the toxin is selected from the group comprising MMAE and MMAF.

29a. An antibody according to paragraph 27a wherein the detectable label is FITC.

30a. An antibody according to any one of paragraphs 1a to 29a binds to the epitope bound by the 10G5 antibody obtainable from the hybridoma WR-10G5-E5.

31a. An antibody that binds to the epitope bound by the 10G5 antibody obtainable from the hybridoma WR-10G5-E5.

32a. The antibody according to paragraph 31a that inhibits the binding of Axl to its ligand Gas6.

33a. The antibody according to either one of paragraphs 31a or 32a that downregulates Axl expression, inhibits Axl receptor signalling, and/or inhibits tumour growth.

34a. An 10G5 antibody obtainable from the hybridoma WR-10G5-E5.

35a. An isolated nucleic acid that comprises a nucleotide sequence encoding an antibody or antibody VH or VL domain of an antibody according to any one of paragraphs 1a to 26a.

36a. A host cell transformed with nucleic acid according to paragraph 35a.

37a. A method of producing an antibody or antibody VH or VL domain, the method comprising culturing host cells according to paragraph 36a under conditions for production of said antibody or antibody VH or VL domain.

38a. A method according to paragraph 37a further comprising isolating and/or purifying said antibody or antibody VH or VL variable domain.

39a. A method according to paragraph 37a or paragraph 38a further comprising formulating the antibody or antibody VH or VL variable domain into a composition including at least one additional component.

40a. A method of obtaining an antibody that binds Axl, the method comprising

-   -   providing by way of addition, deletion, substitution or         insertion of one or more amino acids in the amino acid sequence         of the 10G5 VH domain (SEQ ID NO. 3) one or more VH domains each         of which is an amino acid sequence variant of the 10G5 VH         domain, optionally combining one or more VH domain amino acid         sequence variants thus provided with one or more VL domains to         provide one or more VH/VL combinations; and/or     -   providing by way of addition, deletion, substitution or         insertion of one or more amino acids in the amino acid sequence         of the 10G5 VL domain (SEQ ID NO. 4) a VL domain which is an         amino acid sequence variant of the 10G5 VL domain, and combining         one or more VL domain amino acid sequence variants thus provided         with one or more VH domains to provide one or more VH/VL domain         combinations; and     -   testing the VH domain amino acid sequence variants or VH/VL         combination or combinations for to identify a antibody that         binds Axl.

41a. A method of obtaining an antibody that binds Axl, which method comprises:

-   -   providing starting nucleic acids encoding one or more VH domains         that either comprise a CDR3 to be replaced or lack a CDR3         encoding region, and combining said starting nucleic acid with a         donor nucleic acid encoding the VH CDR3 amino acid sequence of         SEQ ID NO.7 such that said donor nucleic acid is inserted into         the CDR3 region in the starting nucleic acid, so as to provide         product nucleic acids encoding VH domains; or     -   providing starting nucleic acids encoding one or more VL domains         that either comprise a CDR3 to be replaced or lack a CDR3         encoding region, and combining said starting nucleic acid with a         donor nucleic acid encoding the VL CDR3 amino acid sequence of         SEQ ID NO.10 such that said donor nucleic acid is inserted into         the CDR3 region in the starting nucleic acid, so as to provide         product nucleic acids encoding VL domains;     -   expressing the nucleic acids of said product nucleic acids         encoding VH domains and optionally combining the VH domains thus         produced with one or more VL domains to provide VH/VL         combinations, and/or expressing the nucleic acids of said         product nucleic acids encoding VL domains and combining the VL         domains thus produced with one or more VH domains to provide         VH/VL combinations;     -   selecting an antibody comprising a VH domain or a VH/VL         combination that binds Axl; and     -   recovering said antibody that binds Axl and/or nucleic acid         encoding the antibody that binds Axl.

42a. A method according to paragraph 41a or paragraph 41a wherein the antibody that binds Axl is an antibody fragment comprising a VH domain and a VL domain.

43a. A method according to paragraph 42a wherein the antibody fragment is an scFv antibody molecule.

44a. A method according to paragraph 42a wherein the antibody fragment is an Fab antibody molecule.

45a. A method according to paragraph 43a or paragraph 44a further comprising providing the VH domain and/or the VL domain of the antibody fragment in a whole antibody.

46a. A method according to any one of paragraphs 37a to 45a further comprising formulating the antibody that binds Axl or an antibody VH or VL variable domain of the antibody that binds Axl into a composition including at least one additional component.

47a. A method according to any one of paragraphs 37a to 46a further comprising binding an antibody that binds Axl to Axl or a fragment of Axl.

48a. A method comprising binding an antibody that binds Axl according to any one of paragraphs 1a to 29a to Axl or a fragment of Axl.

49a. A method according to paragraph 47a or paragraph 48a wherein said binding takes place in vitro.

50a. A method according to any one of paragraphs 47a to 49a comprising determining the amount of binding of antibody to Axl or a fragment of Axl.

51a. A method according to any one of paragraphs 37a to 46a further comprising use of the antibody in the manufacture of a medicament for treatment of a disease or disorder characterised by overexpression of Axl.

52a. A composition comprising an antibody according to any one of paragraphs 1a to 26a, or an immunoconjugate thereof, in conjunction with a pharmaceutically acceptable excipient.

53a. The composition according to paragraph 52a, further comprising an Immune Checkpoint Modulator, and/or an anti-tumour antibody specific for a target other than Axl.

54a. The composition according to paragraph 53a, wherein the Immune Checkpoint Modulator is an antibody, such as Ipilimumab, Tremelimumab, Pembrolizumab, Mivolumab, AMP-514/MEDI0680, MPDL3280A, MEDI4736, MSB0010718C, BMS-936559, Urelumab, PF05082566, MEDI6469, MEDI6383 (rOX40L), MOXR0916, TRX518, CDX-1127, CP-870,893 or BMS-986016.

55a. The composition according to paragraph 53a, wherein the anti-tumour antibody specific for a target other than Axl is selected from the group consisting of Rituximab, Ibritumomab tiuxetan, tositumomab, Brentuximab vedotin, Gemtuzumab ozogamicin, Alemtuzumab, IGN101, adecatumumab, Labetuzumab, huA33, Pemtumomab, oregovomab, CC49 (minretumomab), cG250, J591, MOv18, MORAb-003 (farletuzumab), 3F8, ch14.18, KW2871, hu3S193, IgN311, Bevacizumab, IM-2C6, CDP791, Etaracizumab, Volociximab, Cetuximab, panitumumab, nimotuzumab 806, Trastuzumab, pertuzumab, MM-121, AMG 102, METMAB, SCH 900105, AVE1642, IMC-A12, MK-0646, R1507, CP 751871, KB004, IllA4, Mapatumumab (HGS-ETR1), HGS-ETR2, CS-1008, Denosumab, Sibrotuzumab, F19, 81C6.

56a. An antibody according to any one of paragraphs 1a to 29a, or the composition according to any one of paragraphs 52a to 55a, for use in a method of treatment.

57a. An antibody or composition according to paragraph 56a for use in a method of treating a proliferative disease.

58a. An antibody or composition according to paragraph 57a where the proliferative disease is cancer.

59a. An antibody or composition according to paragraph 58a where the cancer is metastatic cancer.

60a. Use of an antibody according to any one of paragraphs 1a to 29a, or the composition according to any one of paragraphs 52a to 55a, in the manufacture of a medicament for treatment of a disease or disorder characterised by overexpression of Axl.

61a. A method of treatment of a disease or disorder characterised by overexpression of Axl, the method comprising administering an antibody according to any one of paragraphs 1a to 29a, or the composition according to any one of paragraphs 52a to 55a, to a patient with the disease or disorder or at risk of developing the disease or disorder.

62a. An antibody according to any one of paragraphs 56a to 59a, or method of claim 61a, wherein the method of treatment comprises administering the antibody according to any one of paragraphs 1a to 29a, or the composition according to any one of paragraphs 52a to 55a, in combination with an Immune Checkpoint Modulator and/or an anti-tumour antibody specific for a target other than Axl.

63a. A method according to paragraph 61a wherein the antibody directs the delivery of a pharmaceutical composition to target metastatic cancer cells.

64a. Use of an antibody according to any one of paragraphs 1a to 29a and one or more reagents that allow determination of the binding of said antibody to metastatic cancer cells, in the manufacture of a diagnostic agent for the detection of a disease or disorder characterised by overexpression of Axl.

65a. A method of diagnosis of a disease or disorder characterised by overexpression of Axl, the method comprising administering an antibody according to any one of paragraphs 1 to 29a, or the composition according to any one of paragraphs 52a to 55a, and one or more reagents that allow determination of the binding of said antibody to metastatic cancer cells, to a patient with the disease or disorder or at risk of developing the disease or disorder.

66a. A diagnostic kit comprising an antibody according to any one of paragraphs 1a to 29a and one or more reagents that allow determination of the binding of said member to metastatic cancer cells.

67a. A kit comprising an antibody according to any one of paragraphs 1a to 29a, or the composition according to any one of paragraphs 52a to 55a.

68a. A pharmaceutical composition comprising as active principle an antibody according to paragraphs 1-29a in an effective amount, in conjunction with a pharmaceutically acceptable excipient.

EXAMPLES Example 1: Generation of Mouse Anti-Axl Monoclonal Antibodies

Monoclonal antibodies (MAb) against human Axl receptor were generated by DNA immunization of immunocompetent NMRI mice (Charles River) with a plasmid encoding a fulllength human Axl fused to C-terminal Myc epitope.

Spleen cells from mice showing presence of rhAxl-specific antibodies in the blood were used for fusion with mouse myeloma cells according to standard protocols. The cells were cultured in plates (10⁵ cells per well) with hypoxanthine-aminopterin-thymidine (HAT) medium for hybridoma selection. After twelve days of selection, the supernatants of 14 generated hybridomas were harvested and tested for Axl binding in enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Three positive clones, showing the highest antigen-binding activity after the second round of subcloning by limited dilution, were expanded for large scale antibody production in vitro. The MAbs were purified from the cell culture supernatants by Protein G affinity chromatography.

The antibody clones 10C9 and 10G5 showing specific binding to Axl* cells in flow cytometry were selected for further characterization.

For flow cytometry, the adherent cells in culture were washed with PBS, detached by trypsin (0.25%) treatment for 1 min and hitting culture dish for full detachment. Trypsin was quenched by adding into the tissue flask the complete medium followed by washing the cells with PBS. During the washing steps, the cells were collected by centrifugation at 200 g for 5 min. The antibody was diluted for total concentration in PBS containing 0.02% bovine serum albumin (BSA).

Cell staining was performed using 200 μL of cell suspension comprising 10⁵ cells for 20 min at room temperature. After two washing steps with PBS/0.02% BSA, the cells were resuspended in 200 μL incubated with an APC-conjugated donkey anti-mouse IgG (H+L) secondary antibody (Jackson Laboratories, Cat. no. 715-136-150) at concentration 2 μg/mL for 20 min at room temperature. The stained cells were washed twice with PBS/0.02% BSA and kept on ice before analysis using a BD LSR Fortessa cell analyzer (BD Biosciences).

Example 2: Mouse Monoclonal Antibodies 10C9 and 10G5 do not Cross-React with Other Members of Human Tam Receptor Family

All binding experiments were performed using Biacore 3000 instrument (GE Healthcare) at 25° C. Soluble recombinant antigens corresponding to the extracellular domains of members of the human TAM receptor family, Axl (rhAxl-Fc chimera; R&D Systems, Cat. no. 154-AL), Mer (rhMer-Fc chimera; R&D Systems, Cat. no. 891-MR) and Tyro3 (rhTyro3/Dtk-Fc chimera; R&D Systems, Cat. no. 859-DK) were immobilized on the surface of CM5 sensor chip using amine coupling at the surface density of 393.0, 303.6 and 364.0 resonance units (RU), respectively. The Biacore run was performed in an automatic mode using Binding analysis wizard. Samples containing either MAb 10C9 or MAb 10G5 at concentration 10 μg/mL in HBSEP buffer (GE Healthcare) were injected over the surfaces with immobilized antigens at flow rate of 30 μL/min for 3 min (association) followed by 5 min dissociation.

The results shown in FIG. 1 demonstrate specific binding of the mouse monoclonal antibodies 10C9 and 10G5 to human Axl and no binding to recombinant human Mer and Tyro3 antigens.

Example 3: Mouse Monoclonal Antibodies 10C9 and 10G5 do not Cross-React with Mouse Axl

The binding experiments were performed using Biacore 3000 instrument (GE Healthcare) at 25° C. The soluble recombinant antigens corresponding to human Axl (rhAxl-Fc chimera; R&D Systems, Cat. no. 154-AL), mouse Axl (rmAxl-Fc chimera; R&D Systems, R&D Systems; Cat. no. 854-AX) and human Tyro3 (rhTyro3/Dtk-Fc chimera; R&D Systems, Cat. no. 859-DK) were immobilized on the surface of CM5 sensor chip using amine coupling at the surface density of 1,308.0, 2,115.9 and 1,429.0 RU, respectively. The Biacore runs were performed in an automatic mode using Binding analysis wizard.

The sample containing either MAb 10C9, MAb 10G5 or recombinant mouse (rm) Axl-ligand Gas6 (R&D Systems, Cat. no. 986-GS/CF) at concentration 10 μg/mL in HBS-EP buffer (GE Healthcare) was injected over the surfaces with immobilized antigens at flow rate of 30 μL/min for 3 min (association) followed by 5 min dissociation.

The results shown in FIG. 2 demonstrate specific interaction of MAbs 10C9 and 10G5 with human Axl and no binding to recombinant mouse Axl and human Mer antigens (FIG. 2 , upper and middle panel, respectively). In contrast, mouse Gas6, used as a control, demonstrated strong binding to both human and mouse Axl and somewhat weaker binding to human Tyro3 (FIG. 2 , lower panel).

Example 4: Mouse Monoclonal Antibodies 10C9 and 10G5 Specifically Bind to Axl Receptor from Non-Human Primates

The sequence of Axl receptor from cynomolgus monkey (Macaca fascicularis; SEQ ID NO.43) was retrieved from WO2009062690A1. Based on the sequence, recombinant extracellular domain of cyno-Axl was generated by transient expression in CHO cells as a fusion protein with human Fc. The recombinant cyno-Axl-Fc was purified to homogeneity using Protein A-Sepharose (GE Healthcare). The binding experiments were performed using Biacore 3000 instrument (GE Healthcare) at 25° C. The soluble recombinant antigens corresponding to human Axl (rhAxl-Fc chimera; R&D Systems, Cat. no. 154-AL) and cyno-Axl were immobilized on the surface of CM5 sensor chip using amine coupling at the surface density of 775 and 880 RU, respectively. The Biacore runs were performed in an automatic mode using Binding analysis wizard.

The sample containing either MAb 10C9, MAb 10G5 or human Axl-specific MAb 5F11 (control) at concentration 10 μg/mL in HBS-EP buffer (GE Healthcare) was injected over the surfaces with immobilized antigens at flow rate of 30 μL/min for 3 min (association) followed by 5 min dissociation.

The results shown in FIG. 3 demonstrate strong and specific interaction of MAbs 10C9 and 10G5 with Axl antigens from both human and cynomolgus monkey. In contrast, the control antibody 5F11 showed strong binding to human Axl and lack of cross-reactivity with Axl from cynomolgus monkey.

Example 5: Affinity Determination of Mouse Monoclonal Antibodies 10C9 and 10G5

Affinity determination of anti-Axl antibodies 10C9 and 10G5 was performed at 25° C. by surface plasmon resonance measurements using Biacore 3000 instrument (GE Healthcare). As a solid antigen-coated surface, a sensor chip CM5 with immobilized rhAxl-Fc chimera (R&D Systems, Cat. no. 154-AL) at density 190 RU was used.

For the kinetics measurements, different concentrations of anti-Axl antibodies (from 0.3 to 666.7 nM) in HBS-EP buffer (Biacore, Cat. no. BR-1001-88) were injected at flow rate of 30 μL/min with 3 min injection time followed by 5 min dissociation (buffer alone). After each cycle, the surface was regenerated by 30 sec injection of a regeneration solution (10 mM HCl, 1 M NaCl) at flow rate 50 μL/min.

The mass transfer control experiments demonstrated absence of significant mass transfer limitations for both used MAbs 10C9 and 10G5. An additional, linked reactions control experiment did not reveal linked reactions for both antibodies, since the dissociation phases were practically identical after injection for 1, 3 or 20 min of one analyte concentration (790 nM and 160 nM for MAbs 10C9 and 10G5, respectively).

The kinetic association (on-rate, k_(on)) and dissociation (off-rate, k_(off)) rates were calculated using BIAevaluation software and 1:1 Langmuir binding model. The equilibrium dissociation constant (K_(D)) was calculated as the k_(off)/k_(on) ratio. The half-life (t_(1/2)) of the formed antibody-antigen complexes was calculated as the ln 2/k_(off) ratio.

As shown in FIG. 4 , the mouse MAbs 10C9 and 10G5 demonstrated high affinities in subnanomolar range, with K_(D) values of 0.18 nM and 0.53 nM, respectively.

Example 6: Mouse Monoclonal Antibodies 10C9 and 10G5 Block Binding of Gas6 to Axl

A competitive binding study was performed using Biacore 3000 instrument (GE Healthcare) and Binding Analysis wizard with several cycles of two samples injection. As a first sample, a saturating concentration of MAb 10C9 (790 nM or 120 μg/mL) or 10G5 (160 nM or 24 μg/mL) was injected over the surface of a CM5 sensor chip coated with rhAxl-Fc (using amine coupling) for 3 min at flow rate of 30 μL/min followed by 2.5 min stabilization (HBS-EP buffer alone) before the injection of the second sample. The following second samples were used: recombinant human (rh) Gas6 (R&D Systems, Cat. no. 885-GS), recombinant mouse (rm) Gas6 (R&D Systems, Cat. no. 986-GS/CF) and a panel of anti-Axl antibodies, such as MAB154 (R&D Systems, Cat. no. MAB154), 10C9 and 10G5; all at concentration 25 μg/mL. The second sample was injected for 3 min, followed by 2.5 min stabilization (buffer alone) and regeneration of the surface by 30 sec injection of a regeneration solution (10 mM HCl, 1 M NaCl) at flow rate 50 μL/min.

The results shown in FIG. 5 demonstrated both MAbs 10C9 and 10G5 did not compete for Axl binding with the commercial control antibody MAB154 (R&D Systems). However, the antibodies 10C9 and 10G5 blocked binding of each other and, in addition, inhibited Axl binding by its ligand Gas6, both of human and murine origin.

Example 7: Mouse Monoclonal Antibodies 10C9 and 10G5 Inhibit Growth of Highly Aggressive Breast Carcinoma Cells in Tree-Dimensional (3D) Organotypic Models

A highly aggressive triple-negative human breast cancer cell line MDA-MB-231 (ATCC® HTB-26™) was cultured according to recommended conditions in Dulbecco's Modified Eagle's Medium/Nutrient Mixture F-12 Ham medium supplemented with 10% foetal bovine serum (FBS), glutamine and penicillin and streptomycin. The cells were pre-treated in suspension for at least 1 hour at 37° C., to ensure proper binding of antibodies on the cell surface before they were placed in extracellular matrix. The cells cultures were observed every day and fresh treatments were done every other day. The antibodies were used at concentrations 50-100 μg/mL. Imaging of coverslip 3D assay (35 mm dish) was done on a NIKON light microscopy using both Phase contrast and Hoffman optics. Already at day 3, difference in growth of cells treated with either MAb 10C9 or MAb10G5 and cells treated with a control irrelevant IgG was observed. At day 6, it became evident that cells treated with antibodies 10C9 or 10G5 had significantly inhibited growth and tumour mass development in the extracellular matrix, as compared to the control-treated cells (FIG. 6 ). Nuclei staining revealed that the cells treated with MAb 10G5, despite the inhibited growth, are still viable. Similar effect was observed for the antibody 10C9. This experiment demonstrated that both anti-Axl antibodies 10C9 and 10G5 have the potential to inhibit development of organotypic tumour masses.

Example 8: Antibodies 10C9 and 10G5 Induce Changes in Morphology of 3D Tumour Colonies In Vitro

MDA-MB-231 cells were grown on extracellular matrix and allowed to form the highly aggressive stellate shaped morphology. Stellate-shaped tumour masses were then treated with the control IgG and antibodies 10C9 and 10G5, as described in EXAMPLE 7. Both antibodies 10C9 and 10G5 caused degradation of stellate patterns (FIG. 7 ) accompanied by cell death and DNA fragmentation. These results demonstrated that blocking Axl using specific monoclonal antibodies 10C9 and 10G5 has strong anti-tumour effect in 3D models in vitro.

Example 9: Antibodies 10C9 and 10G5 Induce Axl Receptor Internalization

The expression of Axl receptor protein in MBA-MD-231 cells treated with different antibodies was examined by Western blot analysis. The cells were seeded in a 6-well plate at density of 5×10⁵ cells per well and cultured overnight before treatment initiation. The cells were treated for 20 hrs in the presence of isotype control (mouse IgG2b), anti-Axl antibodies (10C9, 10G5 and MAb #3) at concentrations of 100 μg/mL or multikinase inhibitor Foretinib (targets Met, Ron, Axl, Tie-2, and VEGFR2) at a concentration of 0.5 μM followed by harvesting by centrifugation at 1,200 rpm for 5 min and washing with sterile PBS. The cells were collected by centrifugation and resuspended in NP40-lysis buffer followed by 30 min incubation on ice. The cell lysates were cleared by centrifugation (12,000 rpm, 4° C., 5 min) and the protein concentrations were determined using BCA protein assay. The cell lysate samples comprising 35 μg of total protein were denatured in presence of the reducing agent (Life Technologies) and loaded into the wells of NuPAGE 10% Bis-Tris polyacrylamide (PAA) gel, 1.0 mm×12 well (Invitrogen). The electrophoresis was performed using Bis-Tris SDS running buffer under the recommended conditions (Life Technologies) and the proteins were transfer on PVDF membrane, as described for 2 gels in a manual for XCell II™ Blot Module (Invitrogen) using the transfer buffer with 20% methanol. The membrane was incubated in 10 mL of blocking buffer, TBS/0.1% Tween20 (TBST) with 5% skimmed milk, for 1 hr at room temperature followed by overnight incubation in 5 mL of incubation buffer (TBST with 3% skimmed milk) containing 1:1000 dilution of anti-Axl MAb154 (R&D Systems) at 4° C. The membrane was washed three times for 5 min each with 10 mL of TBST followed by 1 hr incubation with goat-anti mouse IgG (H+L) HRP-conjugated secondary antibody (1:2000) in 5 mL of incubation buffer with gentle rolling at room temperature. Afterwards, the membrane was washed three times for 5 min in 10 mL of TBST and twice with 10 mL of TBS buffer. The membrane was incubated with 1 mL ECL substrate for 1 min at room temperature. Excess substrate solution was aspirated and the blot was visualised using a ChemiDoc™ XRS+ imager (Bio Rad) and Image lab software. As loading control, detection using anti-mouse actin antibody (1:10,000; Sigma) was used under the same conditions.

The results shown in FIG. 8 demonstrated significant reduction of Axl protein in cells treated with MAbs 10C9 and 10G5 compared to the cells treated with either irrelevant IgG or MAb #3. The results indicate that MAbs 10C9 and 10G5 induce internalization and intracellular degradation of Axl receptor.

Example 10: Antibodies 10C9 and 10G5 Block Ligand-Induced Axl Downstream Signaling

The experiments were performed using human cervical cancer derived cell line HeLa (ATCC® CCL-2™). The cells were grown in T175 flasks to 80% confluency in MEM culture medium (Sigma) supplemented with 10% FBS, penicillin-streptomycin and L-glutamine. The cells were washed with PBS and detached by treatment with 0.25% Trypsin/EDTA (Sigma) followed by centrifugation and resuspension in fresh medium (MEM/0.5% FBS). The cells were seeded in Petri dishes (3×10⁶ cells per dish) in MEM medium supplemented with 10% FBS. After three hrs incubation at 37° C., the cells were washed with PBS and kept in starvation medium (MEM/0.5% FBS) overnight. The cells were pre-incubated with anti-Axl antibody 10C9 or 10G5 at concentration 1 μg/mL for 1 hr followed by stimulation with Axl ligand, recombinant mouse Gas6 (R&D Systems), at concentration 10 μg/mL for 20 min. The cell lysates were prepared, as described in EXAMPLE 9, the Western blot analysis was performed using antiphospho-Akt (Ser⁴⁷³) antibody (Cell Signaling) followed by goat anti-rabbit horseradish peroxidase (Jackson ImmunoResearch); the anti-phospho-Akt does not distinguish between AKT1, AKT2, and AKT3, hence the total level of ‘phospho-Akt’ is shown in the blot. Detection with anti-GAPDH antibody (Millipore) was used as loading control.

The results shown in FIG. 9 demonstrated that Axl-specific ligand Gas6 induced strong Axl signalling in HeLa cells that used downstream phosphorylation of Akt on Ser⁴⁷³ as the readout. This signalling could significantly be reduced in the presence of antibody 10C9. Similar results were obtained for the antibody 10G5.

Example 11: Sequencing of Mouse Monoclonal Antibodies 10C9 and 10G5

The hybridoma cells were propagated under standard conditions; 5×10⁶ hybridoma cells were used for mRNA isolation and cDNA synthesis according to standard protocols. For PCR amplification of the genes encoding heavy and light chain variable regions (VH and VL, respectively), Mouse IgG Library Primer Set (Progen, Heidelberg, Germany, Cat. no. F2010) was used. For the hybridoma 10C9, PCR amplification using different primer combinations resulted in 9 sequences from PCR using 5 different primer combinations for the VH gene and in 5 sequences from PCR using 2 different primer combinations for the VL gene. The sequences of the clones VH1 (A7-1) and Vκ2 (E2-2) were selected for further work on the basis of highest homology with the corresponding germline sequences, as determined by nucleotide alignment with IMGT database.

For the hybridoma 10G5, PCR amplification using different primer combinations resulted in 12 sequences from PCR using 6 different primer combinations for the VH gene and in 5 sequences from PCR using 2 different primer combinations for the VL gene. The sequences of the clones VH1 (B6-4) and Vκ1 (F1-3) were selected for further work on the basis of highest homology with the corresponding germline sequences, as determined by nucleotide alignment with IMGT database.

The deduced amino acid sequences of the VH and VL domains for antibodies 10C9 and 10G5 are shown in FIG. 10 . Sequence analysis revealed the presence of a potential N-glycosylation site in CDR1 of the heavy chain (CDR-H1; glycosylation site of ‘NFT’ is shown in bold lettering in FIG. 10 )).

Also included in FIG. 10 is the sequence of a 10G5 VH variant wherein the glutamine (Q) at position 1 of the VH domain is substituted with a glutamate (E); this variant is termed “10G5 [Q1E]”.

Example 12: Generation and Testing Chimeric Monoclonal Antibodies 10C9 and 10G5

The VH and VL sequences retrieved from the murine hybridomas 10C9 and 10G5 were used for generation of the synthetic genes with codon optimization for expression in mammalian cells (GeneArt). These mouse VH and VL genes were ligated in frame with the genetic elements encoding constant domains of the human IgG1 heavy and light (C-kappa) chains, respectively, in an expression vector suitable for antibody production in mammalian cells. Production of the chimeric (mouse variable/human constant) IgG1 antibodies was achieved by transient expression in Chinese Hamster Ovary (CHO) cells followed by purification using Protein A affinity chromatography.

The purified chimeric antibodies (>95% purity) were analysed for binding to Axl-positive breast cancer cell line MDA-MB-231 in flow cytometry. For comparison, the parental mouse MAbs 10C9 and 10G5 were used. For flow cytometry, the adherent cells in culture were washed with PBS, detached by treatment with trypsin (0.25%) for 1 min and hitting culture dish for full detachment. Trypsin was quenched by adding into the tissue flask the complete medium followed by washing the cells with PBS. During the washing steps, the cells were collected by centrifugation at 200 g for 5 min. The antibody was diluted for total concentration in PBS containing 0.02% bovine serum albumin (BSA). Cell staining was performed using 200 μL of cell suspension comprising 10⁵ cells for 20 min at room temperature. The cell-bound antibodies were detected with APC-conjugated donkey anti-human or anti-mouse, respectively, IgG (H+L) F(ab′)₂ fragments (Jackson ImmunoResearch). After two washing steps with PBS/0.02% BSA, the cells were resuspended in 200 μL and kept on ice before analysis on Accuri C6 flow cytometer (BD Biosciences). The results shown in FIG. 11 demonstrated strong binding of the chimeric antibodies to the Axl-positive MDA-MB-231 cells in flow cytometry.

In addition, the Axl-binding properties of the chimeric antibodies c10C9 and c10G5 were tested using Biacore 3000 instrument (GE Healthcare) and a sensor chip CM5 coated with human Axl (rhAxl-Fc chimera; R&D Systems, Cat. no. 154-AL) at the surface density of 1,308.0 RU. The Biacore runs were performed in an automatic mode using Binding analysis wizard. The samples comprising either the chimeric antibodies c10C9 and c10G5 or their murine counterparts at concentration 10 μg/mL in HBS-EP buffer (GE Healthcare) were injected over the surfaces with immobilized antigens at flow rate of 30 μL/min for 3 min (association) followed by 5 min dissociation.

The results shown in FIG. 12 demonstrate that both chimeric antibodies c10C9 and c10G5 bind immobilized Axl with profiles very similar to the binding profiles of the corresponding mouse antibodies derived from the hybridomas 10C9 and 10G5, respectively.

Example 13: Chimeric Antibodies 10C9 and 10G5 Bind Axl with the Same Affinities as the Parental Mouse Antibodies

Affinity determination of the chimeric anti-Axl antibodies c10C9 and c10G5 was performed at 25° C. by surface plasmon resonance measurements using Biacore 3000 instrument (GE Healthcare). As a solid antigen-coated surface, a sensor chip CM5 with immobilized rhAxl-Fc chimera (R&D Systems, Cat. no. 154-AL) at density 190 RU was used.

For the kinetics measurements, different concentrations of anti-Axl antibodies (from 0.3 to 333.3 nM) in HBS-EP buffer (Biacore, Cat. no. BR-1001-88) were injected at flow rate of 30 μL/min with 3 min injection time followed by 5 min dissociation (buffer alone). After each cycle, the surface was regenerated by 30 sec injection of a regeneration solution (10 mM HCl, 1 M NaCl) at flow rate 50 μL/min.

The mass transfer control experiments demonstrated absence of significant mass transfer limitations for both chimeric MAbs c10C9 and c10G5.

The kinetic association (on-rate, k_(on)) and dissociation (off-rate, k_(off)) rates were calculated using BIAevaluation software and 1:1 Langmuir binding model. The equilibrium dissociation constant (K_(D)) was calculated as the k_(off)/k_(on) ratio. The half-life (t_(1/2)) of the formed antibody-antigen complexes was calculated as the ln 2/k_(off) ratio.

As shown in FIG. 13 , both chimeric MAbs c10C9 and c10G5 demonstrated high affinities in subnanomolar range, with K_(D) values of 0.10 nM, somewhat better than the affinities of the parental murine antibodies (see EXAMPLE 5).

Example 14: Chimeric Antibody 10G5 Inhibits Tumor Growth in a Mouse Model of Human Non-Small Cell Lung Cancer

To evaluate the anti-tumour activity of anti-Axl chimeric antibodies in vivo, we used a mouse xenograft model of human non-small cell lung cancer (NSCLC). The human NSCLC A549 cells (ATCC #CCL-185) A549 cells were propagated in vitro as a monolayer culture in DMEM medium supplemented with 10% FBS, 2 mM L-Glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin, 0.01M HEPES buffer, 0.45% D-(+)-glucose, 1 mM sodium pyruvate. Nude mice were implanted subcutaneously (s.c.) into the flank with 5×10⁶ A549 cells resuspended in serum-free medium/Matrigel (1:1). When the tumour size reached 100 mm³ (Day 0 in FIG. 14 ), the animals were randomized and treated with either vehicle (sterile PBS) or anti-Axl chimeric antibody 10G5 at 20 mg/kg, by intraperitoneal (i.p.) injections twice weekly for 4 weeks.

As shown in FIG. 14 , the chimeric antibody 10G5 significantly attenuated growth of A549 tumours compared with the control (P<0.01, as determined by two-way ANOVA); around 40% inhibition was observed after four weeks of treatment.

Example 15: Chimeric Antibody 10G5 Inhibits Tumor Growth in a Mouse Xenograft Model of Human Acute Myeloid Leukaemia

To evaluate the anti-tumour activity of anti-Axl chimeric antibodies in a model of haematological cancer, we used a mouse xenograft model of human acute myeloid leukaemia (AML). The human AML Mv4-11 cells (ATCC #CRL-9591) cells were propagated in suspension in IMDM medium supplemented with 10% FBS, 2 mM L-Glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin. Nude mice were implanted s.c. into the flank with 5×10⁶ Mv4-11 cells resuspended in the mixture of serum-free IMDM medium and Matrigel (1:1). When the tumour size reached 200 mm³ (Day 0 in FIG. 15 ), the animals were randomized and treated with either vehicle (sterile PBS) or anti-Axl chimeric antibody 10G5 at 30 mg/kg, by i.p. injections twice weekly for 4 weeks.

As shown in FIG. 15 , the chimeric antibody 10G5 extremely significantly attenuated growth of Mv4-11 tumours compared with the control (P<0.0001, as determined by two-way ANOVA); around 75% inhibition was observed after three weeks of treatment.

Example 16: Defucosylated Glycoengineered C10G5 (Glymax) Shows Enhanced Anti-Tumor Effect Compared to C10G5 in a Mouse Model of Human Non-Small Cell Lung Cancer

The naked anti-Axl antibodies can prevent tumor growth both by inhibiting the specific signaling pathway of the target receptor and/or through tumor cell killing via its effector functions, such as antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) and/or antibody-dependent cellular phagocytosis (ADCP). Antibodies lacking core fucosylation show a significantly enhanced antibody-dependent cell-mediated cytotoxicity (ADCC) and an increased efficacy of anti-tumor activity.

To compare the anti-tumor effects of two variants of the chimeric antibody c10G5—wt and defucosylated—we used a mouse xenograft model of human non-small cell lung cancer (NSCLC). The human NSCLC A549 cells (ATCC #CCL-185) A549 cells were propagated in vitro as a monolayer culture in DMEM medium supplemented with 10% FBS, 2 mM L-Glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin, 0.01M HEPES buffer, 0.45% D-(+)glucose, 1 mM sodium pyruvate. SCID mice were implanted subcutaneously (s.c.) into the flank with 5×10⁶ A549 cells resuspended in serum-free medium/Matrigel (1:1). When the tumour size reached 130 mm³ (Day 0 in FIG. 15 ), the animals were randomized and treated with either anti-Axl c10G5 or Glymax-c10G5 at 30 mg/kg, by intraperitoneal (i.p.) injections twice weekly for 4 weeks.

As shown in FIG. 16 , the antibody Glymax-c10G5 significantly attenuated growth of A549 tumours compared with the c10G5 (P<0.0001, as determined by two-way ANOVA). The significant difference in activity of wt and defucosylated versions of the chimeric 10G5 indicates importance of antibody-dependent cellular cytotoxicity (ADCC) in inhibition of tumor growth.

Example 17: Framework Variant 1 (FV1) Inhibits Tumor Growth in a Mouse Model of Human Non-Small Cell Lung Cancer

FV1 is an antibody with the CDRs and binding specificity of 10G5, but with multiple substitutions in the V-domain framework regions. To evaluate the anti-tumour activity of anti-Axl FV1 in vivo, we used a mouse xenograft model of human non-small cell lung cancer (NSCLC). The human NSCLC A549 cells (ATCC #CCL-185) A549 cells were propagated in vitro as a monolayer culture in DMEM medium supplemented with 10% FBS, 2 mM L-Glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin, 0.01M HEPES buffer, 0.45% D-(+)-glucose, 1 mM sodium pyruvate. SCID mice were implanted subcutaneously (s.c.) into the flank with 5×10⁶ A549 cells resuspended in serum-free medium/Matrigel (1:1). When the tumour size reached 100 mm³ (Day 18 in FIG. 16 ), the animals were randomized and treated with either vehicle (SYNAGIS) or anti-Axl FV1 at 30 mg/kg, by intraperitoneal (i.p.) injections twice weekly for 2 weeks.

As shown in FIG. 17 , the antibody FV1 significantly attenuated growth of A549 tumours compared with the control (P<0.051, as determined by two-way ANOVA); around 25% inhibition was observed after two weeks of treatment,

Example 18: Glycoengineered FV2 (FV2-GLYMAXX) Potentiates the Effect of Anti-EGFR Treatment on Tumor Growth in a Mouse Model of Human Nonsmall Cell Lung Cancer

FV2-GLYMAXX is a defucosylated antibody with the CDRs and binding specificity of 10G5, but with multiple substitutions in the V-domain framework regions. To evaluate the antitumour activity of FV2-GLYMAXX in vivo, we used a mouse xenograft model of human nonsmall cell lung cancer (NSCLC). The human NSCLC A549 cells (ATCC #CCL-185) A549 cells were propagated in vitro as a monolayer culture in DMEM medium supplemented with 10% FBS, 2 mM L-Glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin, 0.01M HEPES buffer, 0.45% D-(+)-glucose, 1 mM sodium pyruvate. NUDE mice were implanted subcutaneously (s.c.) into the flank with 5×10⁶ A549 cells resuspended in serum-free medium/Matrigel (1:1). When the tumour size reached 100 mm³ (Day 0 in FIG. 18 ), the animals were randomized and treated either with vehicle (SYNAGIS), Erbitux (20 mg/kg) or FV2-GLYMAXX (15 or 30 mg/kg either alone or in combination. Antibodies were administered by intraperitoneal (i.p.) injections twice weekly for 3 weeks.

As shown in FIG. 18 , FV2-GLYMAXX showed moderate anti-tumor activity very similar to the anti-tumor effect of the Anti-EGFR therapeutic antibody cetuximab (Erbitux). For both antibodies used as the single agents, the observed effect was however statistically not significant when compared to the mouse cohort treated with the isotype control antibody (Synagis). Combination of both antibodies resulted in significant tumor growth retardation (P<0.0001; as determined by two-way ANOVA) when compared to isotype control treated animals. The effect was also significant when compared to the groups treated with either FV2-GLYMAXX antibody or Erbitux alone (P<0.05; as determined by two-way ANOVA).

SEQUENCES SEQ ID NO. 1 [10C9 VH domain (nt)] CAGGTCCAACTGCAGCAGCCTGGACCTGAGCTGGTGAAGCCTGGGGCTTCAGTGAAGAT ATCCTGCAAGACTTCTGACTACAATTTCACACGCTACTATATACACTGGGTGAAGCAGAGG CCTGGACAGGGACTTGAGTGGATTGGATGGATTTATCCTGGAACTGGTGATTCTAAATACA ATGAGAAGTTCAAGGGCAGGGCCACACTGACGGCAGACACATCCTCCAGCACTGCCTACA TGCAGCTCAGCTCCCAAACATCTGAGGACTCTGCGGTCTATTTCTGTGCAAGGAATGGTAA CTACTGGTACTTCGATGTCTGGGGCGCAGGGACCGCGGTCACCGTCTCCTCAGCCAAAAC GACACCC SEQ ID NO. 2 [10C9 VL domain (nt)] GATATTGTGATGACGCAGGCTGCACCCTCTGGACCTGTCACTCCTGGAGAGTCAGTATCC ATCTCCTGCAGGTCTAGTAAGAGTCTCCTGCATAGCAATGGCAACACTTACTTATATTGGTT CCTGCAGAGGCCAGGCCAGTCTCCTCAACTCCTGATATATCGGATGTCCAACCTTGCCTC AGGAGTCCCAGACAGGTTCAGTGGCAGTGGGTCAGGAACTGCTTTCACACTGAGAATCAG TAGAGTGGAGGCTGAGGATGTGGGTATCTATTACTGTATGCAACATCGAGAATATCCTTTC ACGTTCGGAGGGGGGACCAAACTGGAAATAAAACGGGCTGATGCTGCACCAACTGTATCC SEQ ID NO. 3 [10C9 VH domain (aa)] QVQLQQPGPELVKPGASVKISCKTSDYNFTRYYIHWVKQRPGQGLEWIGWIYPGTGDSKYNE KFKGRATLTADTSSSTAYMQLSSQTSEDSAVYFCARNGNYWYFDVWGAGTAVTVSS SEQ ID NO. 4 [10C9 VL domain (aa)] DIVMTQAAPSGPVTPGESVSISCRSSKSLLHSNGNTYLYWFLQRPGQSPQLLIYRMSNLASGV PDRFSGSGSGTAFTLRISRVEAEDVGIYYCMQHREYPFTFGGGTKLEIK SEQ ID NO. 5 [10C9 Heavy CDR1] DYNFTRYYIH SEQ ID NO. 6 [10C9 Heavy CDR2] WIYPGTGDSKYNEKFKG SEQ ID NO. 7 [10C9 Heavy CDR3] NGNYWYFDV SEQ ID NO. 8 [10C9 Light CDR1] RSSKSLLHSNGNTYLY SEQ ID NO. 9 [10C9 Light CDR2] RMSNLAS SEQ ID NO. 10 [10C9 Light CDR3] MQHREYPFT SEQ ID NO. 11 [10C9 Heavy FR1] QVQLQQPGPELVKPGASVKISCKTS SEQ ID NO. 12 [10C9 Heavy FR2] WVKQRPGQGLEWIG SEQ ID NO. 13 [10C9 Heavy FR3] RATLTADTSSSTAYMQLSSQTSEDSAVYFCAR SEQ ID NO. 14 [10C9 Heavy FR4] WGAGTAVTVSS SEQ ID NO. 15 [10C9 Light FR1] DIVMTQAAPSGPVTPGESVSISC SEQ ID NO. 16 [10C9 Light FR2] WFLQRPGQSPQLLIY SEQ ID NO. 17 [10C9 Light FR3] GVPDRFSGSGSGTAFTLRISRVEAEDVGIYYC SEQ ID NO. 18 [10C9 Light FR4] FGGGTKLEIK SEQ ID NO. 19 [10G5 VH domain (nt)] CAGGTCCAGCTGCAGCAGTCTGGGGCTGAGCTGGTGAGGCCTGGGGCTTCAGTGAAGCT GTCCTGCAAGGCTTCTGGCTACAGTTTCACTGACTTCTATATAAACTGGGTGAGGCAGAGG CCTGGACAGGGACTTGAGTGGATTGCAAGGATTTTTCCTGGAGGTGATAATACTTACTACA ATGAGAAGTTCAAGGGCAAGGCCACACTGACTGCAGAAGAATCCTCCAGCACTGCCTACA TACAGCTCAGCAGCCTGACATCTGAGGACTCTGCTGTCTATTTCTGTGCAAGACGGGGAC TTTACTATGCTATGGACTACTGGGGTCAAGGAATCTCAGTCACCGTCTCCTCAGCCAAAAC GACACCC SEQ ID NO.20 [10G5 VL domain (nt)] GATGTTTTGATGACCCAAACTCCACTCTCCCTGCCTGTCAGTCTTGGAGATCAAGCCTCCA TCTCTTGCAGATCTAGTCAGAGCCTTGTGCACAGTAATGGAATCCCCTATTTACATTGGTA CCTGCAGAAGCCAGGCCAGTCTCCAAAGCTCCTGATCTACAGAGTTTCCAACCGATTTTCT GGGGTCCCAGACAGGTTCAGTGGCAGTGGATCAGGGACAGATTTCACGCTCAAGATCAG CAGAGTGGAGGCTGAGGATCTGGGAGTTTATTTCTGTTCTCAAGGTACACATGTTCCTCCG ACGTTCGGTGGTGGCACCAAGCTGGAAATCAAACGGGCTGATGCTGCACCAACTGTATCC SEQ ID NO. 21 [10G5 VH domain (aa)] QVQLQQSGAELVRPGASVKLSCKASGYSFTDFYINWVRQRPGQGLEWIARIFPGGDNTYYNE KFKGKATLTAEESSSTAYIQLSSLTSEDSAVYFCARRGLYYAMDYWGQGISVTVSS SEQ ID NO. 22 [10G5 VL domain (aa)] DVLMTQTPLSLPVSLGDQASISCRSSQSLVHSNGIPYLHWYLQKPGQSPKLLIYRVSNRFSGV PDRFSGSGSGTDFTLKISRVEAEDLGVYFCSQGTHVPPTFGGGTKLEIK SEQ ID NO. 23 [10G5 Heavy CDR1] GYSFTDFYIN SEQ ID NO. 24 [10G5 Heavy CDR2] RIFPGGDNTYYNEKFKG SEQ ID NO. 25 [10G5 Heavy CDR3] RGLYYAMDY SEQ ID NO. 26 [10G5 Light CDR1] RSSQSLVHSNGIPYLH SEQ ID NO. 27 [10G5 Light CDR2] RVSNRFS SEQ ID NO. 28 [10G5 Light CDR3] SQGTHVPPT SEQ ID NO. 29 [10G5 Heavy FR1] QVQLQQSGAELVRPGASVKLSCKAS SEQ ID NO. 30 [10G5 Heavy FR2] WVRQRPGQGLEWIA SEQ ID NO. 31 [10G5 Heavy FR3] KATLTAEESSSTAYIQLSSLTSEDSAVYFCAR SEQ ID NO. 32 [10G5 Heavy FR4] WGQGISVTVSS SEQ ID NO. 33 [10G5 Light FR1] DVLMTQTPLSLPVSLGDQASISC SEQ ID NO. 34 [10G5 Light FR2] WYLQKPGQSPKLLIY SEQ ID NO. 35 [10G5 Light FR3] GVPDRFSGSGSGTDFTLKISRVEAEDLGVYFC SEQ ID NO. 36 [10G5 Light FR4] FGGGTKLEIK SEQ ID NO. 37 [Human Axl] MGIQAGEPDPPEEPLTSQASVPPHQLRLGSLHPHTPYHIRVACTSSQGPSSWTHWLPVETPE GVPLGPPENISATRNGSQAFVHWQEPRAPLQGTLLGYRLAYQGQDTPEVLMDIGLRQEVTLE LQGDGSVSNLTVCVAAYTAAGDGPWSLPVPLEAWRPGQAQPVHQLVKEPSTPAFSWPWWY VLLGAVVAAACVLILALFLVHRRKKETRYGEVFEPTVERGELVVRYRVRKSYSRRTTEATLNSL GISEELKEKLRDVMVDRHKVALGKTLGEGEFGAVMEGQLNQDDSILKVAVKTMKIAICTRSELE DFLSEAVCMKEFDHPNVMRLIGVCFQGSERESFPAPVVILPFMKHGDLHSFLLYSRLGDQPVY LPTQMLVKFMADIASGMEYLSTKRFIHRDLAARNCMLNENMSVCVADFGLSKKIYNGDYYRQG RIAKMPVKWIAIESLADRVYTSKSDVWSFGVTMWEIATRGQTPYPGVENSEIYDYLRQGNRLK QPADCLDGLYALMSRCWELNPQDRPSFTELREDLENTLKALPPAQEPDEILYVNMDEGGGYP EPPGAAGGADPPTQPDPKDSCSCLTAAEVHPAGRYVLCPSTTPSPAQPADRGSPAAPGQED GA SEQ ID NO. 38 [Murine Axl] MGRVPLAWWLALCCWGCAAHKDTQTEAGSPFVGNPGNITGARGLTGTLRCELQVQGEPPEV VWLRDGQILELADNTQTQVPLGEDWQDEWKVVSQLRISALQLSDAGEYQCMVHLEGRTFVS QPGFVGLEGLPYFLEEPEDKAVPANTPFNLSCQAQGPPEPVTLLWLQDAVPLAPVTGHSSQH SLQTPGLNKTSSFSCEAHNAKGVTTSRTATITVLPQRPHHLHVVSRQPTELEVAWTPGLSGIYP LTHCNLQAVLSDDGVGIWLGKSDPPEDPLTLQVSVPPHQLRLEKLLPHTPYHIRISCSSSQGPS PWTHWLPVETTEGVPLGPPENVSAMRNGSQVLVRWQEPRVPLQGTLLGYRLAYRGQDTPEV LMDIGLTREVTLELRGDRPVANLTVSVTAYTSAGDGPWSLPVPLEPWRPVSEPPPRAFSWPW WYVLLGALVAAACVLILALFLVHRRKKETRYGEVFEPTVERGELVVRYRVRKSYSRRTTEATLN SLGISEELKEKLRDVMVDRHKVALGKTLGEGEFGAVMEGQLNQDDSILKVAVKTMKIAICTRSE LEDFLSEAVCMKEFDHPNVMRLIGVCFQGSDREGFPEPVVILPFMKHGDLHSFLLYSRLGDQP VFLPTQMLVKFMADIASGMEYLSTKRFIHRDLAARNCMLNENMSVCVADFGLSKKIYNGDYYR QGRIAKMPVKWIAIESLADRVYTSKSDVWSFGVTMWEIATRGQTPYPGVENSEIYDYLRQGNR LKQPVDCLDGLYALMSRCWELNPRDRPSFAELREDLENTLKALPPAQEPDEILYVNMDEGGS HLEPRGAAGGADPPTQPDPKDSCSCLTAADVHSAGRYVLCPSTAPGPTLSADRGCPAPPGQ EDGA SEQ ID NO. 39 [Human Tyro3] MALRRSMGRPGLPPLPLPPPPRLGLLLAALASLLLPESAAAGLKLMGAPVKLTVSQGQPVKLN CSVEGMEEPDIQWVKDGAVVQNLDQLYIPVSEQHWIGFLSLKSVERSDAGRYWCQVEDGGE TEISQPVWLTVEGVPFFTVEPKDLAVPPNAPFQLSCEAVGPPEPVTIVWWRGTTKIGGPAPSP SVLNVTGVTQSTMFSCEAHNLKGLASSRTATVHLQALPAAPFNITVTKLSSSNASVAWMPGAD GRALLQSCTVQVTQAPGGWEVLAVVVPVPPFTCLLRDLVPATNYSLRVRCANALGPSPYADW VPFQTKGLAPASAPQNLHAIRTDSGLILEWEEVIPEAPLEGPLGPYKLSWVQDNGTQDELTVE GTRANLTGWDPQKDLIVRVCVSNAVGCGPWSQPLVVSSHDRAGQQGPPHSRTSWVPVVLG VLTALVTAAALALILLRKRRKETRFGQAFDSVMARGEPAVHFRAARSFNRERPERIEATLDSLGI SDELKEKLEDVLIPEQQFTLGRMLGKGEFGSVREAQLKQEDGSFVKVAVKMLKADIIASSDIEE FLREAACMKEFDHPHVAKLVGVSLRSRAKGRLPIPMVILPFMKHGDLHAFLLASRIGENPFNLP LQTLIRFMVDIACGMEYLSSRNFIHRDLAARNCMLAEDMTVCVADFGLSRKIYSGDYYRQGCA SKLPVKWLALESLADNLYTVQSDVWAFGVTMWEIMTRGQTPYAGIENAEIYNYLIGGNRLKQP PECMEDVYDLMYQCWSADPKQRPSFTCLRMELENILGQLSVLSASQDPLYINIERAEEPTAGG SLELPGRDQPYSGAGDGSGMGAVGGTPSDCRYILTPGGLAEQPGQAEHQPESPLNETQRLL LLQQGLLPHSSC SEQ ID NO. 40 [Human Mer] MGPAPLPLLLGLFLPALWRRAITEAREEAKPYPLFPGPFPGSLQTDHTPLLSLPHASGYQPALM FSPTQPGRPHTGNVAIPQVTSVESKPLPPLAFKHTVGHIILSEHKGVKFNCSISVPNIYQDTTIS WWKDGKELLGAHHAITQFYPDDEVTAIIASFSITSVQRSDNGSYICKMKINNEEIVSDPIYIEVQG LPHFTKQPESMNVTRNTAFNLTCQAVGPPEPVNIFWVQNSSRVNEQPEKSPSVLTVPGLTEM AVFSCEAHNDKGLTVSKGVQINIKAIPSPPTEVSIRNSTAHSILISWVPGFDGYSPFRNCSIQVK EADPLSNGSVMIFNTSALPHLYQIKQLQALANYSIGVSCMNEIGWSAVSPWILASTTEGAPSVA PLNVTVFLNESSDNVDIRWMKPPTKQQDGELVGYRISHVWQSAGISKELLEEVGQNGSRARIS VQVHNATCTVRIAAVTRGGVGPFSDPVKIFIPAHGWVDYAPSSTPAPGNADPVLIIFGCFCGFIL IGLILYISLAIRKRVQETKFGNAFTEEDSELVVNYIAKKSFCRRAIELTLHSLGVSEELQNKLEDVV IDRNLLILGKILGEGEFGSVMEGNLKQEDGTSLKVAVKTMKLDNSSQREIEEFLSEAACMKDFS HPNVIRLLGVCIEMSSQGIPKPMVILPFMKYGDLHTYLLYSRLETGPKHIPLQTLLKFMVDIALGM EYLSNRNFLHRDLAARNCMLRDDMTVCVADFGLSKKIYSGDYYRQGRIAKMPVKWIAIESLAD RVYTSKSDVWAFGVTMWEIATRGMTPYPGVQNHEMYDYLLHGHRLKQPEDCLDELYEIMYS CWRTDPLDRPTFSVLRLQLEKLLESLPDVRNQADVIYVNTQLLESSEGLAQGSTLAPLDLNIDP DSIIASCTPRAAISVVTAEVHDSKPHEGRYILNGGSEEWEDLTSAPSAAVTAEKNSVLPGERLV RNGVSWSHSSMLPLGSSLPDELLFADDSSEGSEVLM SEQ ID NO. 41 [Human Akt3] MSDVTIVKEGWVQKRGEYIKNWRPRYFLLKTDGSFIGYKEKPQDVDLPYPLNNFSVAKCQLMK TERPKPNTFIIRCLQWTTVIERTFHVDTPEEREEWTEAIQAVADRLQRQEEERMNCSPTSQIDN IGEEEMDASTTHHKRKTMNDFDYLKLLGKGTFGKVILVREKASGKYYAMKILKKEVIIAKDEVAH TLTESRVLKNTRHPFLTSLKYSFQTKDRLCFVMEYVNGGELFFHLSRERVFSEDRTRFYGAEIV SALDYLHSGKIVYRDLKLENLMLDKDGHIKITDFGLCKEGITDAATMKTFCGTPEYLAPEVLEDN DYGRAVDWWGLGVVMYEMMCGRLPFYNQDHEKLFELILMEDIKFPRTLSSDAKSLLSGLLIKD PNKRLGGGPDDAKEIMRHSFFSGVNWQDVYDKKLVPPFKPQVTSETDTRYFDEEFTAQTITIT PPEKCQQSDCGMLGNWKK SEQ ID NO. 42 [Human Gas6] MAPSLSPGPAALRRAPQLLLLLLAAECALAALLPAREATQFLRPRQRRAFQVFEEAKQGHLER ECVEELCSREEAREVFENDPETDYFYPRYLDCINKYGSPYTKNSGFATCVQNLPDQCTPNPC DRKGTQACQDLMGNFFCLCKAGWGGRLCDKDVNECSQENGGCLQICHNKPGSFHCSCHSG FELSSDGRTCQDIDECADSEACGEARCKNLPGSYSCLCDEGFAYSSQEKACRDVDECLQGR CEQVCVNSPGSYTCHCDGRGGLKLSQDMDTCEDILPCVPFSVAKSVKSLYLGRMFSGTPVIR LRFKRLQPTRLVAEFDFRTFDPEGILLFAGGHQDSTWIVLALRAGRLELQLRYNGVGRVTSSG PVINHGMWQTISVEELARNLVIKVNRDAVMKIAVAGDLFQPERGLYHLNLTVGGIPFHEKDLVQ PINPRLDGCMRSWNWLNGEDTTIQETVKVNTRMQCFSVTERGSFYPGSGFAFYSLDYMRTPL DVGTESTWEVEVVAHIRPAADTGVLFALWAPDLRAVPLSVALVDYHSTKKLKKQLVVLAVEHT ALALMEIKVCDGQEHVVTVSLRDGEATLEVDGTRGQSEVSAAQLQERLAVLERHLRSPVLTFA GGLPDVPVTSAPVTAFYRGCMTLEVNRRLLDLDEAAYKHSDITAHSCPPVEPAAA SEQ ID NO. 43 [Axl from Macaca fascicularis; also called herein ″Cyno Axl″] MAWRCPRMGRVPLAWCLALCGWVCMAPRGTQAEESPFVGNPGNITGARGLTGTLRCQLQV QGEPPEVHWLRDGQILELADSTQTQVPLGEDEQDDWIVVSQLRIASLQLSDAGQYQCLVFLG HQNFVSQPGYVGLEGLPYFLEEPEDRTVAANTPFNLSCQAQGPPEPVDLLWLQDAVPLATAP GHGPQRNLHVPGLNKTSSFSCEAHNAKGVTTSRTATITVLPQQPRNLHLVSRQPTELEVAWT PGLSGIYPLTHCTLQAVLSDDGMGIQAGEPDPPEEPLTLQASVPPHQLRLGSLHPHTPYHIRVA CTSSQGPSSWTHWLPVETPEGVPLGPPENISATRNGSQAFVHWQEPRAPLQGTLLGYRLAY QGQDTPEVLMDIGLRQEVTLELQGDGSVSNLTVCVAAYTAAGDGPWSLPVPLEAWRPGQAQ PVHQLVKETSAPAFSWPWWYILLGAVVAAACVLILALFLVHRRKKETRYGEVFEPTVERGELV VRYRVRKSYSRRTTEATLNSLGISEELKEKLRDVMVDRHKVALGKTLGEGEFGAVMEGQLNQ DDSILKVAVKTMKIAICTRSELEDELSEAVCMKEFDHPNVMRLIGVCFQGSERESFPAPVVILPF MKHGDLHSFLLYSRLGDQPVYLPTQMLVKFMADIASGMEYLSTKRFIHRDLAARNCMLNENM SVCVADFGLSKKIYNGDYYRQGRIAKMPVKWIAIESLADRVYTSKSDVWSFGVTMWEIATRGQ TPYPGVENSEIYDYLRQGNRLKQPADCLDGLYALMSRCWELNPQDRPSFTELREDLENTLKAL PPAQEPDEILYVNMDEGGGYPEPPGAAGGADPPTQLDPKDSCSCLTSAEVHPAGRYVLCPST APSPAQPADRGSPAAPGQEDGA SEQ ID NO. 44 [Linker] GGGGS SEQ ID NO. 45 [10G5 (Q1E) VH domain (aa)] QVQLQQSGAELVRPGASVKLSCKASGYSFTDFYINWVRQRPGQGLEWIARIFPGGDNTYYNE KFKGKATLTAEESSSTAYIQLSSLTSEDSAVYFCARRGLYYAMDYWGQGISVTVSS

Biological Deposits

The present disclosure refers to two different hybridoma cell lines. The two hybridoma cell lines have been deposited in accordance with the ‘Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure’, with details as set out below.

UT-10C9-B9 Depositary European Collection of Cell Cultures (ECACC) Institution Public Health England Porton Down Salisbury Wiltshire SP4 0JG United Kingdom Date of deposit →16 Dec. 2015 Accession number →15121601 Characteristics →Hybridoma - B-Lymphocyte; Species - M. musculus (mouse); Morphology - lymphoblast; Immunogen - human Axl extracellular domain; Immunocyte donor - NMRI mice; Immortal partner X63.Ag8.653; product Ig class/sub-class - IgG2b WR-10G5-E5 Depositary European Collection of Cell Cultures (ECACC) Institution Public Health England Porton Down Salisbury Wiltshire SP4 0JG United Kingdom Date of deposit →16 Dec. 2015 Accession number →15121602 Characteristics →Hybridoma - B-Lymphocyte; Species - M. musculus (mouse); Morphology - lymphoblast; Immunogen - human Axl extracellular domain; Immunocyte donor - NMRI mice; Immortal partner X63.Ag8.653; product Ig class/sub-class - IgG1 

1. An antibody that binds to the epitope bound by the antibody obtainable from either: A) the hybridoma UT-10C9-B9; or B) the hybridoma WR-10G5-E5.
 2. The antibody according to claim 1, that inhibits the binding of Axl to its ligand Gas6.
 3. The antibody according to either one of claim 1 or 2 that downregulates Axl expression, inhibits Axl receptor signalling, and/or inhibits tumour growth.
 4. The antibody according to any one of claims 1 to 3 that binds Axl and that comprises: A) an antibody VH domain comprising a VH CDR3 with the amino acid sequence of SEQ ID NO.7 and optionally one or more VH CDR's with an amino acid sequence selected from SEQ ID NO.6 and SEQ ID NO.5; and/or an antibody VL domain comprising one or more VL CDR's with an amino acid sequence selected from SEQ ID NO.8, SEQ ID NO.9 and SEQ ID NO.10; or B) an antibody VH domain comprising a VH CDR3 with the amino acid sequence of SEQ ID NO.25 and optionally one or more VH CDR's with an amino acid sequence selected from SEQ ID NO.24 and SEQ ID NO.23; and/or an antibody VL domain comprising one or more VL CDR's with an amino acid sequence selected from SEQ ID NO.26, SEQ ID NO.27 and SEQ ID NO.28.
 5. An antibody according to any one of claims 1 to 4 comprising an antibody VH domain comprising either: A) the VH CDR's with the amino acid sequences of SEQ ID NO.5, SEQ ID NO.6 and SEQ ID NO.7, which antibody competes for binding to Axl with an Axl binding domain of an antibody comprising the 10C9 VH domain (SEQ ID NO. 3) and the 10C9 VL domain (SEQ ID NO. 4); or B) the VH CDR's with the amino acid sequences of SEQ ID NO.23, SEQ ID NO.24 and SEQ ID NO.25, which antibody competes for binding to Axl with an Axl binding domain of an antibody comprising the 10G5 VH domain (SEQ ID NO. 21) and the 10G5 VL domain (SEQ ID NO. 22).
 6. An antibody according to any one of claims 1 to 5 comprising either: A) the 10C9 VH domain (SEQ ID NO. 3); or B) the 10G5 VH domain (SEQ ID NO. 21).
 7. An antibody according to claim 6 comprising either: A) the 10C9 VL domain (SEQ ID NO. 4); or B) the 10G5 VL domain (SEQ ID NO. 22).
 8. A variant of an antibody according to any one of claims 1 to 7, wherein the variant comprises one or more amino acid sequence alterations in one or more framework regions and/or one or more CDRs.
 9. An antibody according to any one of claims 1 to 8, wherein the antibody comprises: (i) all or a portion of an antibody heavy chain constant region and/or of an antibody light chain constant region; (ii) a whole antibody; or (iii) an antigen-binding antibody fragment.
 10. An antibody according to claim 9, wherein the whole antibody is an IgG antibody; or wherein the antigen-binding antibody fragment is a single domain antibody, Fv, scFv, dsFv, Fd, Fab, F(ab′)2, minibody, diabody, single-chain diabody, tandem scFv, TandAb, bi-body, tri-body, kappa(lambda)-body, BiTE, DVD-Ig, SIP, SMIP, or DART.
 11. An antibody according to any one of claims 1 to 10 wherein the antibody is a humanized or a chimeric antibody.
 12. An antibody according to any one of claims 1 to 11 wherein the Axl is human Axl.
 13. An antibody according to any one of claims 1 to 12 that binds Axl with a K_(D) no greater than 6×10⁻¹⁰ M.
 14. An antibody according to any one of claims 1 to 13 that binds Axl with a k_(on) no lower than 8×10⁵ M⁻¹s⁻¹.
 15. An antibody according to any one of claims 1 to 14 that specifically binds primate Axl.
 16. An antibody according to any one of claims 1 to 15 that: (i) binds murine Axl with a K_(D) greater than 10⁻³ M; (ii) binds human Mer with a K_(D) greater than 10⁻³ M; and/or (iii) binds human Tyro3 with a K_(D) greater than 10⁻³ M.
 17. An antibody according to any one of claims 1 to 16 that inhibits the binding of Axl to Gas6.
 18. An antibody according to any one of claims 1 to 17 that down-regulates expression of the Axl receptor.
 19. An antibody according to any one of claims 1 to 18 that increases the rate of Axl receptor internalization.
 20. An antibody according to any one of claims 1 to 19, wherein the antibody inhibits Axl receptor downstream signalling.
 21. An antibody according to any one of claims 1 to 20 that increases the rate of cell death.
 22. An antibody according to any one of claims 1 to 21 that inhibits tumour growth.
 23. An antibody according to any one of claims 1 to 22 that is conjugated to a detectable label, enzyme, or toxin, optionally via a peptidyl bond or linker.
 24. An antibody obtainable from either: A) the hybridoma UT-10C9-B9; or B) the hybridoma WR-10G5-E5.
 25. An isolated nucleic acid that comprises a nucleotide sequence encoding an antibody or antibody VH or VL domain of an antibody according to any one of claims 1 to
 23. 26. A host cell transformed with nucleic acid according to claim
 25. 27. A method of producing an antibody or antibody VH or VL domain, the method comprising culturing host cells according to claim 26 under conditions for production of said antibody or antibody VH or VL domain.
 28. A composition comprising an antibody according to any one of claims 1 to 23, or an immunoconjugate thereof, in conjunction with a pharmaceutically acceptable excipient.
 29. The composition according to claim 28, further comprising an Immune Checkpoint Modulator, and/or an anti-tumour antibody specific for a target other than Axl.
 30. An antibody according to any one of claims 1 to 23, or the composition according to claim 23, for use in a method of treatment.
 31. An antibody or composition according to claim 30 for use in a method of treating a proliferative disease.
 32. An antibody or composition according to claim 31 where the proliferative disease is cancer.
 33. An antibody or composition according to claim 32 where the cancer is metastatic cancer.
 34. Use of an antibody according to any one of claims 1 to 23, or the composition according to either one of claim 28 or claim 29, in the manufacture of a medicament for treatment of a disease or disorder characterized by overexpression of Axl.
 35. A diagnostic kit comprising an antibody according to any one of claims 1 to 24 and one or more reagents that allow determination of the binding of said member to metastatic cancer cells.
 36. A kit comprising an antibody according to any one of claims 1 to 23, or the composition according to either one of claim 28 or claim
 29. 